Q: Given the table of mole relationships, how many chloride ions are present in 1 mole of BaCl$$_2$$?

$$2 \times 6.02 \times 10$$^{23}$$

Question 1

Which of the following best describes the law illustrated by the balanced equation $$2 \mathrm{H}_2 + \mathrm{O}_2 \rightarrow 2 \mathrm{H}_2\mathrm{O} as $$shown in the first image?

Accepted Answer

The law of conservation of mass

Question 2

In the reaction $$2 \mathrm{H}_2 + \mathrm{O}_2 \rightarrow 2 \mathrm{H}_2\mathrm{O}$$, what is the correct mole ratio of hydrogen to oxygen to water?

Accepted Answer

$$2:1:2$$

Question 3

If you start with 4 moles of $$\mathrm{H}_2$$ and excess $$\mathrm{O}_2$$, how many moles of $$\mathrm{H}_2\mathrm{O}$$ can be produced according to the equation $$2 \mathrm{H}_2 + \mathrm{O}_2 \rightarrow 2 \mathrm{H}_2\mathrm{O}$$?

Accepted Answer

4 moles

Question 4

A pie chart shows three elements in a compound. If the green section represents 51.4%, the blue section 42.1%, and the red section 6.5%, which compound is most likely represented?

Accepted Answer

C$$_{12}H$_{22}O$_{11} ($$sucrose)

Question 5

Given the table of mole relationships, how many chloride ions are present in 1 mole of BaCl$$_2$$?

Accepted Answer

$$2 	imes 6.02 	imes 10$$^{23}$$

Question 6

Which of the following statements about coefficients and subscripts in chemical equations is correct?

Accepted Answer

Coefficients change the amount of substance, subscripts change the identity.

Question 7

A sample contains $$9.81 	imes 10$$^{23}$$ chloride ions. How many moles of MgCl_2$ does this represent?

Accepted Answer

$$0.815$$ mol

Question 8

What is the empirical formula of a compound containing 36.8 g nitrogen and 63.25 g oxygen?

Accepted Answer

N$$_2O$_3$$

Question 9

A reaction produces 1.12 g of Zn(NO$$_3$$)$$_2$$ when the theoretical yield is 1.39 g. What is the percent yield?

Accepted Answer

$$80.6\%$$

Question 10

Which of the following is a correct example of a combination reaction?

Accepted Answer

$$\mathrm{C} (s) + \mathrm{O}_2 (g) \rightarrow \mathrm{CO}_2 (g)$$

Question 11

How many grams of CO$$_2$$ are produced when 3.81 g of C$$_4H$_{10} is $$burned in excess oxygen? ($$2 \mathrm{C}_4\mathrm{H}_{10} + 13 \mathrm{O}_2 \rightarrow 8 \mathrm{CO}_2 + 10 \mathrm{H}_2\mathrm{O}$$, MM C$$_4H$_{10} = 58.14 g/$$mol, MM CO$$_2 = 44.01 g/$$mol)

Accepted Answer

11.5 g

Question 12

Which of the following best describes a limiting reactant?

Accepted Answer

The reactant that is completely consumed and limits the amount of product formed.

Question 13

If 2.49 mol of Fe(OH)$$_3 is $$present, how many grams does this represent? (MM Fe(OH)$$_3 = 106.88 g/$$mol)

Accepted Answer

266 g

Question 14

A chemical reaction requires 5.00 mmol NaCl. How many grams should be massed using the laboratory scale? (MM NaCl = 58.44 g/mol)

Accepted Answer

0.292 g

Question 15

What is the molecular formula of a compound with empirical formula HCO$$_2$$ and molar mass 90.0 g/mol?

Accepted Answer

H$$_2C$_2O$_4$$

Question 16

Which of the following is a correct example of a double replacement reaction?

Accepted Answer

$$\mathrm{Na}_2\mathrm{CO}_3 (aq) + 2 \mathrm{AgNO}_3 (aq) \rightarrow 2 \mathrm{NaNO}_3 (aq) + \mathrm{Ag}_2\mathrm{CO}_3 (s)$$

Question 17

How many molecules are in 0.346 mol of C$$_2H$_4$$?

Accepted Answer

$$2.08 	imes 10$$^{23}$$

Question 18

Which of the following is true about the percent yield of a reaction?

Accepted Answer

It is the ratio of actual yield to theoretical yield, multiplied by 100.

Stoichiometry: Calculations with Chemical Formulas and Equations

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