Type of Reaction
Law of Conservation and Empirical vs. Molecular
GFM and Percent Composition
Mole Calculation
Balancing and Mole Ratio
100
Which terms identify types of chemical reactions?
(1)decomposition and sublimation
(2)decomposition and synthesis
(3)deposition and sublimation
(4)deposition and synthesis
2
100
Which type of formula represents the simplest whole-number ratio of atoms of the elements in a compound?
(1) molecular formula (3) empirical formula
(2) condensed formula (4) structural formula
(3) Empirical
100
What is the gram-formula mass of (NH4)3PO4?
(1) 112 g/mol (3) 149 g/mol
(2) 121 g/mol (4) 242 g/mol
(3) 149 g/mol
100
Determine the total mass of 2 moles of H2O.
2*18=36g
100
Given the balanced equation representing a reaction:
Al2(SO4)3 + 6NaOH → 2Al(OH)3 + 3Na2SO4
The mole ratio of NaOH to Al(OH)3 is
(1) 1:1 (3) 3:1
(2) 1:3 (4) 3:7
(3) 3:1
200
C6H12O6(aq) → 2C2H5OH(aq) + 2CO2(g)
Identify the type of reaction
Decomposition
200
Given the formula for a compound:
Which molecular formula and empirical formula represent this compound?
(1) C2HNO2 and CHNO
(2) C2HNO2 and C2HNO2
(3) C4H2N2O4 and CHNO
(4) C4H2N2O4 and C2HNO2
(4) C4H2N2O4 and C2HNO2
200
The gram-formula mass of a compound is 27 grams. The mass of 1.0 mole of this compound is
(1) 1.0 g (3) 27 g
(2) 2.7 g (4) 270 g
(3) 27 g
200
Determine the total mass of 4 moles of NH3.
68.12276 g
200
The coefficients in a balanced equation represent
(1) the mass ratios of the substances in the reaction
(2) the mole ratios of the substances in the reaction
(3) the total number of electrons in the reaction
(4) the total number of elements in the reaction
(2) the mole ratios of the substances in the reaction
300
Which equation represents a single replacement reaction?
3
300
Given two formulas representing the same compound:
Formula A Formula B
CH4 C4H8
Which statement describes these formulas?
(1) Formulas A and B are both empirical.
(2) Formulas A and B are both molecular.
(3) Formula A is empirical, and formula B is molecular.
(4) Formula A is molecular, and formula B is empirical.
(3) Formula A is empirical, and formula B is molecular.
300
What is the percent composition by mass of sulfur in the compound MgSO4 (gram-formula mass = 120. grams per mole)?
(1) 20.% (3) 46%
(2) 27% (4) 53%
(2) 27%
300
The element boron, a trace element in Earth’s crust, is found in foods produced from plants. Boron has only two naturally occurring stable isotopes, boron-10 and boron-11.
One sample of a green vegetable contains 0.0035 gram of boron. Determine the total number of moles of boron in this sample.
0.00032377 mol
300
Baking soda, NaHCO3, can be commercially produced during a series of chemical reactions called the Solvay process. In this process, NH3(aq), NaCl(aq), and other chemicals are used to produce NaHCO3(s) and NH4Cl(aq).
To reduce production costs, NH3(aq) is recovered from NH4Cl(aq) through a different series of reactions. This series of reactions can be summarized by the overall reaction represented by the unbalanced equation below.
__NH4Cl+ __CaO → __NH3 + __H2O + __CaCl2
Balance the equation for the overall reaction used to recover NH3(aq) using the smallest whole-number coefficients. [1]
2 NH4Cl+ 1 CaO → 2 NH3 + 1 H2O + 1 CaCl2
2:1 --> 2:1:1
400
In which type of chemical reaction do elements in two compounds switch?
(1) synthesis
(2) decomposition
(3) single replacement
(4) double replacement
4
400
Given the balanced equation representing a reaction:
2H2 + O2 → 2H2O
What is the mass of H2O produced when 10.0 grams of H2 reacts completely with 60.0 grams of O2?
(1) 70.0 g (3) 180. g
(2) 90.0 g (4) 800. G
(1) 70.0 g
400
Baking soda, NaHCO3, can be commercially produced during a series of chemical reactions called the Solvay process. In this process, NH3(aq), NaCl(aq), and other chemicals are used to produce NaHCO3(s) and NH4Cl(aq).
To reduce production costs, NH3(aq) is recovered from NH4Cl(aq) through a different series of reactions. This series of reactions can be summarized by the overall reaction represented by the unbalanced equation below.
2 NH4Cl+ 1 CaO → 2 NH3 + 1 H2O + 1 CaCl2
Determine the percent composition by mass of carbon in baking soda (gram-formula mass = 84 grams per mole). [1]
14%
400
Vitamin C, also known as ascorbic acid, is water soluble and cannot be produced by the human body. Each day, a person’s diet should include a source of vitamin C, such as orange juice. Ascorbic acid has a molecular formula of C6H8O6 and a gram-formula mass of 176 grams per mole.
Determine the number of moles of vitamin C in an orange that contains 12.3 g of vitamin C. [1]
0.0699 moles of vitamin C
400
Balance Chemical Reaction Below:
___ NH3 + ___ O2 → ___ NO + ___ H2O
4 NH3 + 5 O2 → 4 NO + 6 H2O
4:5 -->4:6
500
Describe a synthesis reaction in terms of reactants and products.
A+B--> AB
500
Many breads are made by adding yeast to the dough, causing the dough to rise. Yeast is a type of microorganism that produces the catalyst zymase, which converts glucose, C6H12O6, to ethanol and carbon dioxide gas. The balanced equation for this reaction is shown below.
C6H12O6(aq) → 2C2H5OH(aq) + 2CO2 (g)
Determine the total mass of ethanol produced when 170. grams of glucose reacts completely to form ethanol and 132 grams of carbon dioxide. [1]
38 grams of ethanol
500
Vitamin C, also known as ascorbic acid, is water soluble and cannot be produced by the human body. Each day, a person’s diet should include a source of vitamin C, such as orange juice. Ascorbic acid has a molecular formula of C6H8O6 and a gram-formula mass of 176 grams per mole.
In the space below, show a numerical setup for calculating the percent composition by mass of oxygen in ascorbic acid.
54.54%
500
Paintball is a popular recreational activity that uses a metal tank of compressed carbon dioxide or nitrogen to launch small capsules of paint. A typical tank has a volume of 508 cubic centimeters. A 340.-gram sample of carbon dioxide is added to the tank before it is used for paintball. At 20.°C, this tank contains both CO2(g) and CO2(ℓ). After a paintball game, the tank contains only CO2(g).
Determine the total number of moles of CO2 added to the tank before it is used for paintball.
(340)/((2*15.9994)+(12.011))= 7.72555203614 mol
500
Given the balanced equation:
2 C + 3 H2 → C2H6
If a student reacts 60 moles of H2, how many moles of C2H6 would he produce?
20 moles of C2H6