Question 1

Which of the following best describes the purpose of balancing a chemical equation?

Accepted Answer

To make sure the number of atoms of each element is the same on both sides of the equation.

Question 2

Given the unbalanced equation: $$\mathrm{C_4H_{10} + O_2$ \rightarrow CO_2$ + H_2O}$$, what is the correct coefficient for $$\mathrm{O_2$}$$ after balancing?

Accepted Answer

$$13$$

Question 3

In the balanced equation $$2\mathrm{H_2$} (g) + 1\mathrm{O_2$} (g) \rightarrow 2\mathrm{H_2O} (g)$$, what does the coefficient '2' in front of $$\mathrm{H_2$}$$ represent?

Accepted Answer

The number of molecules of hydrogen gas required.

Question 4

When balancing the equation $$\mathrm{Na_3PO_4 + Ca(NO_3$)_2 \rightarrow $$NaNO_3$$ + Ca_3$(PO_4$)_2}$$, what is the sum of the coefficients in the balanced equation?

Accepted Answer

$$8$$

Question 5

Which step is NOT recommended when balancing chemical equations?

Accepted Answer

Change the subscripts of compounds to balance the equation.

Question 6

A student balances the equation $$\mathrm{C_2H_5SH + O_2$ \rightarrow CO_2$ + H_2O + SO_2$}$$ and finds the coefficients to be $$2, 4.5, 2, 3, 1. $$What is the total sum of the coefficients?

Accepted Answer

$$10.5$$

Question 7

Why is it important to never change the subscripts of a chemical formula when balancing equations?

Accepted Answer

Changing subscripts alters the identity of the compound.

Question 8

If you balance the equation $$\mathrm{C_4H_{10} + O_2$ \rightarrow CO_2$ + H_2O}$$, what is the coefficient for $$\mathrm{CO_2$}$$?

Accepted Answer

$$4$$

Question 9

Which of the following is a balanced chemical equation?

Accepted Answer

$$2\mathrm{H_2$} + O_2$ \rightarrow 2\mathrm{H_2O}$$

Question 10

In a combustion reaction of butane ($$\mathrm{C_4H_{10}}$$), which products are always formed?

Accepted Answer

$$\mathrm{CO_2$}$$ and $$\mathrm{H_2O}$$

Question 11

What is the first step in balancing a chemical equation according to the provided materials?

Accepted Answer

Set up a list for the elements in reactants and products.

Question 12

If a balanced equation has fractional coefficients, what should you do to finalize the equation?

Accepted Answer

Multiply all coefficients by the denominator to obtain whole numbers.

Question 13

Which of the following is a common mistake when balancing chemical equations?

Accepted Answer

Changing the subscripts of compounds.

Question 14

In the reaction $$\mathrm{C_2H_5SH + O_2$ \rightarrow CO_2$ + H_2O + SO_2$}$$, which element should be balanced last?

Accepted Answer

Oxygen

Question 15

What is the balanced equation for the reaction $$\mathrm{Na_3PO_4 + Ca(NO_3$)_2 \rightarrow $$NaNO_3$$ + Ca_3$(PO_4$)_2}$$?

Accepted Answer

$$2\mathrm{Na_3PO_4} + 3\mathrm{Ca(NO_3$)_2} \rightarrow 6\mathrm{$$NaNO_3$$} + 1\mathrm{Ca_3$(PO_4$)_2}$$

Question 16

After balancing the equation $$\mathrm{C_4H_{10} + O_2$ \rightarrow CO_2$ + H_2O}$$, what is the sum of all coefficients?

Accepted Answer

$$15$$

Question 17

Which of the following equations is NOT balanced?

Accepted Answer

$$\mathrm{Na_3PO_4 + Ca(NO_3$)_2 \rightarrow $$NaNO_3$$ + Ca_3$(PO_4$)_2}$$

Question 18

In a real-world scenario, why is it important for a pharmaceutical company to balance chemical equations when synthesizing a drug?

Accepted Answer

To ensure the correct dosage and avoid harmful side products.

Question 19

Which of the following statements about coefficients in chemical equations is TRUE?

Accepted Answer

Coefficients represent the number of molecules or moles involved in the reaction.

Balancing Chemical Equations: Principles and Practice

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