Question 1

Which of the following best describes a balanced chemical equation?

Accepted Answer

The number of atoms for each element is the same on both sides of the equation.

Question 2

What is the correct balanced equation for the reaction of solid iron(III) oxide with carbon to produce iron and carbon dioxide?

Accepted Answer

$$2Fe_2O_3(s) + 3C(s) \rightarrow 4Fe(s) + 3CO_2(g)$$

Question 3

Which of the following is a decomposition reaction?

Accepted Answer

$$2HgO(s) \xrightarrow{\Delta} 2Hg(l) + O_2$(g)$$

Question 4

Which symbol in a chemical equation indicates that the reactants are heated?

Accepted Answer

$$\Delta$$

Question 5

What type of reaction is represented by the following equation? $$2C_2H_6(g) + 7O_2(g) \rightarrow 4CO_2(g) + 6H_2O(g)$$

Accepted Answer

Combustion

Question 6

Which of the following is the correct set of coefficients to balance the equation: $$Al(s) + H_2SO_4(aq) \rightarrow Al_2$(SO_4$)_3(aq) + H_2$(g)$$?

Accepted Answer

$$2, 3, 1, 3$$

Question 7

A reaction in which two compounds exchange ions to form two new compounds is called:

Accepted Answer

Double replacement

Question 8

Which of the following equations is balanced?

Accepted Answer

$$2Na_3PO_4(aq) + 3MgCl_2(aq) \rightarrow Mg_3$(PO_4$)_2(s) + 6NaCl(aq)$$

Question 9

Which of the following best describes a single replacement reaction?

Accepted Answer

One element replaces another in a compound.

Question 10

In the reaction $$CH_4(g) + 2O_2(g$$) \xrightarrow{\Delta} $$CO_2(g) + 2H_2O(g$$) + 	ext{Energy}$$, what is the role of O_2$?

Accepted Answer

Reactant

Question 11

Which of the following is NOT a sign that a chemical reaction has occurred?

Accepted Answer

The reactants and products have the same properties.

Question 12

What is the correct classification for the reaction: $$3Ba(s) + N_2$(g) \rightarrow Ba_3N_2(s)$$?

Accepted Answer

Combination

Question 13

Which of the following is a correct description of the symbol $$(aq) in a $$chemical equation?

Accepted Answer

The substance is dissolved in water.

Question 14

A student writes the equation $$H_2(g$$) + $$O_2(g$$) \rightarrow H_2O(g)$$. What is the main error in this equation?

Accepted Answer

The equation is not balanced.

Question 15

Which of the following reactions is a double replacement reaction?

Accepted Answer

$$Na_2SO_4(aq) + $$BaCl_2$$(aq) \rightarrow $$BaSO_4$$(s) + 2NaCl(aq)$$

Question 16

Which of the following is the correct balanced equation for the reaction of aluminum with iron(II) oxide?

Accepted Answer

$$2Al(s) + 3FeO(s) \rightarrow 3Fe(s) + Al_2O_3(s)$$

Question 17

Which of the following is a real-life example of a combustion reaction?

Accepted Answer

Burning natural gas in a stove to produce heat and water vapor.

Question 18

When balancing a chemical equation, why is it important to use coefficients rather than changing subscripts in chemical formulas?

Accepted Answer

Changing subscripts alters the identity of the substance.

Question 19

Which of the following best describes the products of a combustion reaction involving a hydrocarbon?

Accepted Answer

Carbon dioxide and water

Question 20

In the reaction $$2Na_3PO_4(aq) + 3MgCl_2(aq) \rightarrow Mg_3$(PO_4$)_2(s) + 6NaCl(aq)$$, what is the physical state of $$Mg_3$$($$PO_4)_2$?

Accepted Answer

Solid

Chemical Equations, Reactions, and Equilibrium: Study Notes

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