Chemistry College

## Answers

**Answer 1**

Taking into account definition of percent yield, the **percent yield** of carbon dioxide is 30.90%

Reaction stoichiometry

In first place, the balanced reaction is:

2 CH₃CH₃ + 7 O₂ → 4 CO₂ + 6 H₂O

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:

CH₃CH₃: 2 molesO₂: 7 molesCO₂: 4 molesH₂O: 6 moles

The molar mass of the compounds is:

CH₃CH₃: 30 g/moleO₂: 32 g/moleCO₂: 44 g/moleH₂O: 18 g/mole

Then, by** reaction stoichiometry**, the following **mass quantities **of each compound participate in the reaction:

CH₃CH₃: 2 moles ×30 g/mole= 60 gramsO₂: 7 moles ×32 g/mole= 224 gramsCO₂: 4 moles ×44 g/mole= 176 gramsH₂O: 6 moles ×18 g/mole= 108 grams

Limiting reagent

The limiting reagent is one that is **consumed first **in its entirety, determining the amount of product in the reaction. When the limiting reagent is finished, the chemical reaction will stop.

Limiting reagent in this case

To determine the limiting reagent, it is possible to use a simple **rule of three** as follows: if by stoichiometry 224 grams of O₂ reacts with 60 grams of CH₃CH₃, 16.7 grams of O₂ reacts with how much mass of CH₃CH₃?

mass of CH₃CH₃= (16.7 grams of O₂× 60 grams of CH₃CH₃)÷ 224 grams of O₂

*mass of CH₃CH₃= 4.47 grams*

But 4.47 grams of CH₃CH₃ are not available, 2.71 grams are available. Since you have less mass than you need to react with 16.7 grams of O₂, **CH₃CH₃** will be the **limiting reagent**.

Percent yield

The percent yield is the ratio of the actual return to the theoretical return expressed as a percentage.

The percent yield is calculated as the experimental yield divided by the theoretical yield multiplied by 100%:

**percent yield= (actual yield÷ theoretical yield)×100%**

where the theoretical yield is the amount of product acquired through the complete conversion of all reagents in the final product, that is, it is the maximum amount of product that could be formed from the given amounts of reagents.

Theoretical yield of CO₂

Considering the limiting reagent, the following rule of three can be applied: if by reaction stoichiometry 60 grams of CH₃CH₃ form 176 grams of CO₂, 2.71 grams of CH₃CH₃ form how much mass of CO₂?

mass of CO₂= (2.71 grams of CH₃CH₃× 176 grams of CO₂)÷ 60 grams of CH₃CH₃

*mass of CO₂= 7.96 grams*

Then, the **theoretical yield **of CO₂ is 7.96 grams.

Percent yield for the reaction in this case

In this case, you know:

actual yield= 2.46 gramstheorical yield= 7.96 grams

Replacing in the definition of percent yields:

percent yield= (2.46 grams÷ 7.96 grams)×100%

Solving:

*percent yield= 30.90%*

Finally, the **percent yield** for the reaction is 30.90%.

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## Related Questions

How many moles of magnesium is 5.01 x 1022 atoms of magnesium?

### Answers

**Answer**

**Explanation**

Note that a mole of any substance has 6.02 x 10²³ atoms of that substance.

**Let x represent** the mole of magnesium present in 5.01 x 10²² atoms of magnesium.

Therefore,

[tex]\begin{gathered} 1\text{ mole }=\text{6.02}\times10^{23}\text{ atoms} \\ x\text{ mole }=5.01\times10^{22}\text{ atoms} \\ \end{gathered}[/tex]

**Cross multiply, and divide both sides by 6.02 x 10²³ atoms to get x**

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The reaction of carbon with oxygen to produce carbon monoxide is an example of which type (or class) of reaction?2C(s) + O2(g) → 2CO(g)single replacementendothermicdouble replacementcatalyticcombination

### Answers

Answer:

**Combination. Option E** is correct.

Explanations:

Given the **chemical reaction between carbon and oxygen** expressed as:

[tex]2C(s)+O_2(g)\rightarrow2CO(g)[/tex]

From the equation, you can see that carbn combines with oxygen atom to produce carbonmonoxide. This type of reaction is known as the **combination reaction** since it involves the **reaction of two element**s to produce a compound (carbon monoxide)

Based on the explanations above, we can concude that the r**eaction of carbon with oxygen** to produce carbon monoxide is an example of a** combination reaction.**

A student found that it required 25.8 mL of a 1.60 M NaOH solution to neutralize 15.0 mL of a certain H 2SO 4 solution which react according to the equation: 2 NaOH + H 2SO 4 → Na 2SO 4 + 2 H 2O. The molarity of the sulfuric acid solution

### Answers

1) Check if the chemical reaction is balanced.

[tex]2NaOH+H_2SO_4=Na_2SO_4+2H_2O[/tex]

2) Moles of NaOH in the reaction.

[tex]\text{Moles of NaOH =1.60 M}\cdot\frac{25.8\text{ mL}}{\square}\cdot\frac{1\text{ L}}{1000\text{ mL}}=\text{ 0.0413 moles of NaOH}[/tex]

3) Moles of neutralized acid.

[tex]\text{Moles of H}_2SO_4\text{ =0.0413 moles of NaOH}\cdot\frac{1molesofH_2SO_4}{2\text{ moles of NaOH}}=0.0206molesofH_2SO_4[/tex]

4) Molarity of H2SO4

[tex]\text{Molarity of H}_2SO_4=\frac{0.0206molesofH_2SO_4}{15.0\text{ mL}}\cdot\frac{1000\text{ mL}}{1\text{ L}}=1.38MH_2SO_4[/tex]

HELP ASAP 50 POINTS WILL MARK BRAINLY REAL ANSERS ONLY

### Answers

**Answer:A**

**Explanation:because i did the test **

**Component** **Q** is more powerful in explaining a scientific **phenomenon** because peer conformation and support are characteristics of a **theory**.

**Scientific** phenomena are events that can be witnessed in the natural and artificial worlds that make people wonder and pose questions. A theory is a logical **interpretation** or explanation of a phenomenon or set of occurrences. For instance, the theory of **evolution** through natural selection is a hypothesis because it explains the variety of life on earth.

In addition to offering accurate **explanations** or interpretations, theories also serve additional objectives. Here, we examine three additional **goals** of theories: the organizing of well-understood phenomena, the forecasting of outcomes in novel circ*mstances, and the development of fresh lines of inquiry.

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calculate the net force acting on the box in the following. refer to the screenshot below.

### Answers

**Answer:**

6 N to the left, or -6 N

unbalanced

**Explanation:**

The forces are two 3 N forces. The forces are additive, so 3+3 = 6, so the answer is 6 N to the left.

Since the net force isn't 0, the forces are unbalanced (aka the block will move since there is a force pushing the block)

Provide the number of moles of Ca^ 2- ions contained in 0.125 L of 0.455 M solution of Ca 3 (PO 4 ) 2

### Answers

**Answer:**

Moles of Ca3(PO4)2 = 0.455 M * 0.125 L = 0.0569 mol

1 Mole of Ca3(PO4)2 = 3 moles of Ca2+ ions

Thus, moles of Ca2+ ion = 3 * 0.0569 = 0.1707 ~ 0.171 moles

The number of moles of **ions** in a solution can be calculated using the **molarity** and volume of the solution. The number of moles of **Ca ²⁺ ions **contained in 0.125 L of 0.455 M solution of Ca₃ (PO₄) ₂ is 0.0170 moles.

What is molarity?

**Molarity** is a term used to represent the **concentration** of the solution. Mathematically it is the ratio of number of moles of solute to the volume of solution in liters.

The **molarity **of the **calcium phosphate** solution is given 0.455 M and its volume is 0.125 L. Thus, the no.of moles of calcium phosphate in the solution is calculated as follows:

no.of moles of Ca₃ (PO₄) ₂ = molarity × volume

= 0.455 M × 0.125 L

= 0.0568 moles.

It is clear from the formula that one mole of calcium phosphate contains 3 moles of Ca ²⁺ ions. Therefore, the number of moles of **calcium ions** in 0.0568 moles of calcium phosphate is calculated as follows:

No. of moles of Ca ²⁺ ions = 0.0568 × 3

= 0.0170 moles.

Hence the number if moles of **calcium ions** in 0.125 L of 0.455 M calcium phosphate is 0.0170 moles.

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What is the standard cell notation for an electrolytic cell with aluminum and gold electrodes? (answer choices in screenshot)

### Answers

Oxidation takes place at the anode. Reduction takes place at the cathode. Oxidation takes place on the left and recution takes place on the right.

The standard cell notation for an electrolytic cell with alumium and gold electrodes:

[tex]Al(s)\lbrack Al^{3+}(aq)\parallel Au^+(aq)]Au(s)[/tex]

To determine which metal undergoes oxidation and which undergoes reduction we use the standard cell potentetial of the metals. Au is the stronger oxidising agent of the two and so it is likely to undergo reduction and so the Al will undergo oxidation.

Answer: **A**

Gizmo Student exploration melting point

### Answers

Every substance has a specific **temperature **range at which it changes from one phase (solid, liquid, or gas) to another.

Measure the melting, boiling, and/or sublimation points of several substances using a realistic **melting point** device to see what these phase changes appear like on a tiny scale.

Make assumptions about the relative potency of the forces binding these compounds together based on the **transition** points.

By placing a small amount of an organic solid into a capillary tube, attaching it to the thermometer's stem in the centre of a heating bath, and gradually heating the bath, one can ascertain the **temperature** at which melting starts and ends.

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Balance the following equation MnO2(s) + HCI(aq) = Cl2(g) + MnCl2(aq) + H2O(I)

### Answers

[tex]\text{MnO}_2\text{ + 4HCl }\rightarrow Cl_2+MnCl_2+2H_2O[/tex]

A population is a group of plants or animals of the same ______ that live in an area.

### Answers

**Answer:**

Species. A population is a group of plants or animals of the same species that live in an area.

Predict the chemical formula for the ionic compound formed by V³⁺ and NO₂⁻

### Answers

You can see that NO₂⁻ has an oxidation number of -1 and V³⁺ has an oxidation number of +3.

When we state the chemical formula of these compounds, we need to have that the algebraic sum of the oxidation numbers must be zero. In this case, we have that the sum is -1 + 3 = 2, it is incorrect because we need to have the result of zero.

For this problem, we can multiply three times NO₂⁻ obtaining that the oxidation number is -3, so the algebraic sum would be: (-1)(3) + 3 = -3 + 3 = 0. This means that the chemical formula will have three times NO₂⁻ bonded with V³⁺ and it would be:

[tex]V(NO_2)_3.[/tex]

3. Calculate the equilibrium constant ( Ke ) for the reaction below if the equilibrium mixture for the reaction was found o contain [ H₂S ] 0.25 M. [ H₂ ] = 1 M , and [ S₂ ] -0.2 M. 2H₂S ( g ) 2H₂ ( g ) + S2 ( g )

### Answers

The equilibrium constant relates the concentrations of the products and reactants in the chemical equilibrium. To calculate it we can apply the following equation.

For the reaction: aA + bB ---> cC + dD

Equlibrium constant (Ke) will be:

[tex]K=\frac{\lbrack C\rbrack^c\times\lbrack D\rbrack^d}{\lbrack A\rbrack^a\times\lbrack B\rbrack^b}[/tex]

The letters in square brackets refer to the concentration raised to the respective coefficient. Now we replace the known values:

[tex]\begin{gathered} K=\text{ }\frac{\lbrack H_2\rbrack^2\times\lbrack S_2\rbrack^1}{\lbrack H_2S\rbrack^2} \\ K=\frac{\lbrack1M\rbrack^2\times\lbrack0.2M\rbrack^1}{\lbrack0.25M\rbrack^2} \\ K=\frac{1M^2\times0.2M}{0.0625M^2} \\ K=3.2M \end{gathered}[/tex]

**So, the equilibrium constant (Ke) will be 3.2M**

What is the correct name for AIN?a. Aluminum nitrideb. Aluminum nitratec. Aluminum mononitrided. Aluminum mononitrate

### Answers

**Answer**:

a. Aluminum nitride

**Explanation**:

The compound AlN is a salt made up of Al and N.

Analyzing the oxidation states of each element, we can see that Aluminum acts with 3+ (because it has only one oxidation state), so Nitrogen need to interact with an oxidation state of 3-, for the molecule to be neutral.

Due to the nitrogen acts with 3- the name of the salt will be **Aluminum nitride**.

Ca(s) + 2H₂O(l) → Ca(OH)₂(aq) + H₂(g) 14. Calcium reacts with water according to the above reaction. What volume of hydrogen gas, at standard temperature and pressure, is produced from 0.200 moles of calcium?

### Answers

According to the** stoichiometry**, 0.4 ml of **hydrogen** gas is produced from 0.2 moles of calcium .

What is stoichiometry?

It is the determination of proportions of elements or compounds in a chemical reaction. The related relations are based on **law of conservation of mass** and** law of combining weights and volumes.**

Stoichiometry is used in** quantitative analysis** for measuring concentrations of substances present in the sample.

In the given problem, 1 mole of calcium produces 1 mole of hydrogen gas.

Given 0.2 moles of calcium , so mass of calcium by number of moles formula,mass=number of moles×molar mass=0.2×40.07=8.014 g

As 40.07 g of calcium produces 2 g hydrogen

∴8.014 g calcium produces 8.014×2/40.07=0.4 ml.

Thus, the** volume** of **hydrogen **gas produced from 0.2 moles of calcium at standard temperature and pressure is 0.4 ml.

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Measurements show that the energy of a mixture of gaseous reactants decreases by 181.kj during a certain chemical reaction, which is carried out at a constant pressure. Furthermore, by carefully monitoring the volume change it is determined that -86.kj of work is done on the mixture during the reaction.

Calculate the change in enthalpy of the gas mixture during the reaction. Round your answer to 2 significant digits.

### Answers

The **change in enthalpy** of the gas mixture during the **reaction** is - 95 kj.

The formula for the change in internal energy is given by:

**ΔU = ΔH + W**

**ΔU** = the change in inter energy = -181 kj ( decreased)

** ΔH** = the change in enthalpy

**W** = work done = -86 kj

substituting the values in the formula we get :

ΔU = ΔH + W

- 181 kj = ΔH - 86 kj

ΔH = -181 kj + 86 kj

**ΔH** = - 95 kj

**Measurements** show that the energy of a mixture of gaseous reactants **decreases** by 181.kj during a certain chemical reaction, which is carried out at a constant pressure. Furthermore, by carefully monitoring the volume change it is determined that -86.kj of **work** is done on the mixture during the reaction. The **change in enthalpy** of the gas mixture during the reaction is - 95 kj.

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How many grams of gold will be produced from 213.46g AuPO4? At. Wt.: Sn = 119g/mol; Au

= 197g/mol; P = 31g/mol; O = 16g/mol

### Answers

The amount of **gold** that can be produced from 213.46g **AuPO₄** is equal to 143.7g.

What is a mole?

A **mole** is a standard unit that can be used to determine the huge number of **quantities** of ions, atoms, molecules, or other particular particles. The mass of the 1 mole of any element is known as **atomic mass (in grams)** and the mass of one mole of any compound is called **molar mass.**

The number of units in one mole was found to be approximately 6.023 × 10 ²³ also called **Avogadro’s constant.**

Given, the mass of the AuPO₄ = 213.46 g

The **molar mass **of the AuPO₄ = 197 + 31 + 4(16) = 292 g/mol

The **number of moles o**f the AuPO₄ = 213/292 = 0.729 mol

If the mole of AuPO₄ will produce **one mole** of the Au.

Then 0.729 mol of the** AuPO₄ **will produce Au = 0.729 mol

The **mass** of the Au (in grams) = 0.729 ×197 = 143.7 g/mol

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Choose the words to finish the sentence.

The sinking of ocean crust back into the mantle when it meets continental crust is

Choose...

, and this occurs at

Choose...

.

### Answers

The sinking of the **ocean** crust back into the mantle when it meets continental crust is referred to as **subduction** , and this process occurs at the **ocean** trenches.

What is Subduction?

This is referred to as a geological process which occurs when there is collision between two **tectonic** plates in the earth in which one of the plate sinks into the **mantle** underneath the other plate.

During this process of **subduction**, the **ocean** crust sinks back into the mantle when it meets continental crust and it occurs mainly at the **ocean** trenches thereby making the options provided the correct choice.

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A student conducts an experiment to determine how the temperature of water affects the time for sugar to dissolve. In each trial, the student uses a different amount of sugar and a different temperature of water. What is wrong with this experimental design? Responses The student needs to perform more trials. The student needs to perform more trials. The student does not have a dependent variable. The student does not have a dependent variable. The student changed too many variables. The student changed too many variables. The student did not change enough variables.

### Answers

**Answer:**

The student changed too many variables.

Calculations of Ksp

a) calculate the concentrations of dissolved PbI2, Pb+2 and I-1 ions when Ksp = 1.35 x 10-9

b) calculate the Ksp of Ag3CrO4 when the concentration of silver cations is 4.16 x 10-6 mol/L when you know that this dissociation occurs: Ag3CrO4 ↔ 3 Ag+ + CrO4-3

### Answers

1) The **solubility **of the ions are;

lead II ions = 6.96 * 10^-4 M

iodide ions = 3.48 * 10^-4 M

2) The **Ksp **of silver chromate is 8.98 * 10^-22

What is the concentration of the solution?

We know that the **Ksp **has to do with the **equilibrium constant** that shows the extent to which a substance dissolves in water. We can see that the equation of the **dissolution **can be written for each of the reactants.

a) [tex]PbI2 (s) --- > Pb^{2+} (aq) + 2I^{-} (aq)[/tex]

Now we can see that the **Ksp **is obtained from;

Ksp = [[tex]Pb^{2+}[/tex]] [2[tex]I^{-}[/tex]]^2

Let the solubility be x

Ksp = 4x^3

x = ∛ 1.35 x 10^-9/4

x = 6.96 * 10^-4 M

Hence;

Concentration of lead II ions = 6.96 * 10^-4 M

Concentration of iodide ions = 6.96 * 10^-4 /2 = 3.48 * 10^-4 M

b) In order to obtain the** solubility product** of the silver chromate solution;

Let the solubility of each of the ions be x

We can see that;

Ksp = [3x]^3 [x]

Ksp = 3x^4

Ksp = 3(4.16 x 10^-6)^4

Ksp = 8.98 * 10^-22

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This alkyl halide can be prepared by electrophilic addition of HBr to 2 different alkenes. Draw them

### Answers

This **alkyl halide** can be prepared by electrophilic addition of HBr to 2 different alkenes because of alkenes undergo hydrogenation in presence of acid and base when HBr can added to the different alkyl 3-methyl-hex-2-ene, 3-methyl-hex-3-ene and 3-methylene hexane

Hydrogenation is the** chemical reaction** in which molecular hydrogen and another compound and element usually in presence of catalyst such as nickel, palladium or platinum and this process is commonly employed to reduce or saturated organic compound

Addition of hydrogen and halogen to the double bond or triple bond based on markovnikov rule of addition and when HBr is added to CH3- CH=CH2 then Br is added to CH group and H is added to the CH₂ group of the alkene and if the reaction is carried in the presence of any peroxide then reverse addition is taking place

Then different alkyl structure such as 3-methyl-hex-2-ene, 3-methyl-hex-3-ene and 3-methylene hexane and image is given below

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The energy diagram shown represents the chemical reaction between solid ammonium chloride and solid barium hydroxide octahydrate:2NH4Cl(s)+Ba(OH)2⋅8H2O(s)→2NH3(aq)+BaCl2(aq)+10H2O(l)The ΔH for this reaction is 54.8 kJ . How much energy would be absorbed if 27.1 g of NH4Cl reacts?Express your answer with the appropriate units.Answer= (value)/(units)

### Answers

According to the chemical equation, the reaction absorbs 54.8 kJ per 2 moles of NH4Cl because that's the stoichiometry coefficient of this molecule.

Now, we need to find the number of moles in each mole of NH4Cl.

[tex]\begin{gathered} N=14.0067 \\ H_4=4\cdot(1.00784)=4.03136 \\ Cl=35.453 \end{gathered}[/tex]

Then, we add them to find the molar mass.

[tex]NH_4Cl=53.49\cdot\frac{g}{\text{mol}}[/tex]

This means that 1 mole of NH4Cl equals 53.49 grams.

At last, we multiply the mass of NH4Cl (27.1 g) by two ratios, the first ratio is about the molar mass, and the second ratio is about the amount of heat per moles.

[tex]27.1g\cdot\frac{1\text{mol}}{53.49g}\cdot\frac{54.8kJ}{2\text{mol}}=\frac{1485.08}{106.98}kJ=13.88kJ[/tex]

**Therefore, the amount of energy that would be absorbed is 13.88 kJ.**

What does it mean for a strong base to be in equilibrium?

The position of equilibrium lies far to the right, with products being favored

O The position of equilibrium bes far to the left, with products being favored

There is a great deal of base and very few bns.

There is an equal amount of reactants and products.

### Answers

The **strong base **to be in **equilibrium** refers to shifting towards the left side of the reaction and far away from the right side i.e option 1

**What do you understand by equilibrium?**

A system is at an **equilibrium **when all of its **external forces** are in balance.

Generally, In any acid-base reaction, the** equilibrium **will favor that side of reaction which moves the proton towards the **stronger base.**

Let us consider the given reaction

**HCl (acid) + NaOH (strong base) NaCl + H20**

As per the reaction,** equilibrium **will shift towards the left side as it involves the abstraction of the **proton ** by the** base.**

Hence, the answer is option 1 first which means the **position of equilibrium lies far to right.**

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195 ml of 0.355 m nacl is added to a 0.500 l volumetric flask and the flask is filled with water. calculate the [na⁺] concentration in the diluted solution.

### Answers

**Answer:**

0.286 M

**Explanation:**

This is a great example of a practice problem that requires you to use the formula for dilution calculations.

To make it more interesting, let's assume that you're not familiar with that problem.

The most important thing to remember about a dilution is the the number of moles of solute must remain constant.

That is, the number of moles of solute present in the initial solution must be equal to the number of moles of solute present in the diluted solution.

Since molarity is defined as moles of solute per liter of solution, keeping the number of moles of solute constant allows you to decrease concentration by increasing the total volume of the solution.

195 ml of 0.355 ml NaCl is added to a 0.500 ml volumetric flask and the flask is filled with water. The [ Na⁺ ] concentration in the diluted solution is **138.45 M**

What is concentration ?

**Concentration **is calculated by dividing a constituent's abundance by the mixture's total volume. Mass concentration, **molar concentration**, number **concentration**, and volume concentration are four different categories of mathematical description.

**Molarity **is the number of moles of solute per liter of **solution **and mole fraction is the proportion of **solute **moles to all other moles of substances present. Parts per thousand grams, **mass **percentage, the ratio of the solute's mass to the solution's mass multiplied by 100.

M₁ V₁ = M₂ V₂

0.355 × 195 = M₂ × 0.500

M₂ = 0.355 × 195 ÷ 0.500

**138.45 M**

Thus, The [ Na⁺ ] concentration in the diluted solution is **138.45 M**

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Solid calcium phosphate and aqueous sulfuric acid solution react to give calcium sulfate, which comes out of solution as a solid. The other product is phosphoric acid, which remains in solution. Write an equilibrium equation for the reaction using complete formulas for the compounds with phase labels.

### Answers

**Answer: i also need help on the same question :( **

**Explanation:**

7.30×10² +2.80×10³

[? ] × 10²]

### Answers

**Scientific notation is the way that scientists handle large numbers and small numbers. For example, instead of writing 0.000 000 0056, they write 5.6 × 10⁻⁹.**

**We can think of 5.6 × 10⁻⁹ as the product of two numbers: 5.6 (the digits) and 10⁻⁹ (the power of 10).**

**Here are some examples of scientific notation.**

**1000 = 1 × 10³; 7354 = 7.354 × 10³**

**100 = 1 × 10²; 482 = 4.82 × 10²**

**10 = 1 × 10¹; 89 = 8.9 × 10¹**

**1 = 1 × 10⁰; 6 = 6 × 10⁰**

**1/10 = 0.1 = 1 × 10⁻¹; 0.32 = 3.2 × 10⁻¹**

**1/100 = 0.01 = 1 × 10⁻²; 0.053 = 5.3 × 10⁻²**

**1/1000 = 0.001 = 1 × 10⁻³; 0.0078 = 7.8 × 10⁻³**

**The exponent of 10 is the number of places we must shift the decimal point to get the scientific notation.**

**Each place the decimal moves to the left increases the exponent by 1.**

**Each place the decimal point moves to the right decreases the exponent by 1.**

**EXAMPLE:**

**Write the following numbers in scientific notation: 1001;**

**6 926 300 000; -392; 0.000 000 13; -0.0038**

**Solution:**

**1.001 × 10³; 6.9263 × 10⁹; -3.92 × 10²; 1.3 × 10⁻⁷; -3.8 × 10⁻³**

**Hope this helps!**

What is the name of the ionic compound CuBr

### Answers

**Answer:**

Copper(I) bromide

**Explanation:**

Copper has oxidation numbers of +1 or +2

Bromide has a common charge of -1

This can be called Copper I bromide more precisely .or somewhat redudanately Copper mono bromide.

An older form of naming would be Cupous Bromide. Indicating a +1 charge on Copper. Cupric Bromide would be CuBr2 indicating a + 2 charge.

What is the expected product from the reaction of potassium with oxygen?K2O2K2OKO2KO

### Answers

Potassium oxide is an ionic compound formed by combining potassium and oxygen. It carries the chemical formula K2O.

So, this is expected product from the reaction of potassium with oxygen because of the following:

To get the net charge of the compound equal to zero, we need to satisfy the equation K2O. So that's the answer.

Why is crystal of oxalic acid regarded as a primary standard solution ?

### Answers

**Answer:**

dwn

**Explanation:**

Oxalic acid solution is a primary standard because it is highly pure, stable and does not change its concentration with environmental factors. > Coming to option B, Sodium thiosulphate, it is a secondary standard reagent. Sodium thiosulphate is also called hypo.

2HC2H3O2 + Na2CO3 = h20 + co3 + 2nac2h3o2

### Answers

Answer:

Na2CO3+2HC2H3O2→CO2+H2O+2NaC2H3O2

Explanation:

Label Each Compound With a VariableLabel each compound (reactant or product) in the equation with a variable to represent the unknown coefficients.aNa2CO3+bHC2H3O2=cCO2+dH2O +fNaC2H3O2Create a System of EquationsCreate an equation for each element (Na, C, O, H) where each term represents the number of atoms of the element in each reactant or product.Na:2a+0b=0c+0d+1f

C:1a+2b=1c+0d+2f

O:3a+2b=2c+1d+2f

H:0a+4b=0c+2d+3f

Solve For All VariablesUse substitution, gauss elimination, or a calculator to solve for each variable.

Simplify the result to get the lowest, whole integer values.

a = 1 (Na2CO3)

b = 2 (HC2H3O2)

c = 1 (CO2)

d = 1 (H2O)

f = 2 (NaC2H3O2)

Substitute Coefficients and Verify Result

Na2CO3+2HC2H3O2= CO2+ H2O +2NaC2H3O2

Reactants Products

Na 2 2 ✔️

C 5 5 ✔️

O 7 7 ✔️

H 8 8 ✔️

Since there is an equal number of each element in the reactants and products of Na2CO3 + 2HC2H3O2 = CO2 + H2O + 2NaC2H3O2, the equation is balanced.

Can you please help me with 1-13

### Answers

**Answer:**

E, C, A, 90, 5, D, B, D, D, D and B, A C and E, A, E

**Explanation:**

1. is correct, it is E

2. is C, not D. D is when the liquid is freezing/when the solid is melting.

3. the answer is A. B is when the gas is condensing or when the liquid is boiling.

4. 90 temperature units. This is the boiling point. Technically the substance can still condense below this point until 5 temperature units, or D, but ignore that.

5. 5 temperature units.

6. D, this is where the solid and liquids exchange states (ie melting/freezing)

7. B, this is where boiling and condensing occurs

8. Crystallisation is a fancy word for freezing. The melting and freezing points are the same, so D

9. D. Fusion means freezing.

10. D and B.

11. A, C, and E

12. A has the highest temperature and the highest kinetic and potential energy

13. E has the lowest kinetic and potential energy