Review and Chapter 3

Question 1

Kinetic energy

Answer 1

energy for moving objects

Question 2

Potential energy

Answer 2

stored energy; something that can happen but hasn’t happened yet

Question 3

Thermal energy

Answer 3

energy from heat

Question 4

Electrical energy

Answer 4

forces of attraction and repulsion between charged particles

Question 5

Chemical energy

Answer 5

net attraction of electrons and nuclei in molecules and compounds

Question 6

Nuclear energy

Answer 6

energy that holds protons and neutrons in the nucleus of an atom

Question 7

Conservation of energy

Answer 7

• energy is neither created nor destroyed

- energy may be transferred or transformed

Question 8

Which of the following elements is likely to display similar chemical properties?

a) Na and Mg
b) Al and Si
c) O and S
d) Cr and Mn
e) Be and B

Answer 8

• look for the ones in the same group of the periodic table

c) O and S

Question 9

What is the molar mass of phosphoric acid, H3PO4?

Answer 9

(1.0083) + (30.97) + (164) = 97.994 g/mol

Question 10

How many significant figures are there in the answer for the following problem?
(6.21010^13)(6.0110^23)/(345)(3.000)

Answer 10

three

Question 11

A candle is burning in front of you. What transformation in energy from the list below did not occur?

a) chemical energy was converted to radiant energy
b) chemical energy was converted to sound energy
c) kinetic energy was converted to potential energy
d) chemical energy was converted to thermal energy
e) thermal energy was converted to sound energy

Answer 11

c) kinetic energy was converted to potential energy

Question 12

What is the molar mass of C34H32FeN4O4?

Answer 12

(12.0134) + (1.00832) + 55.85 + (14.014) + (16.004) = 616.486 g/mol

Question 13

Write the balanced combustion reaction for methanol.

Answer 13

3O2 + 2CH4O —–> 2CO2 + 4H2O

Question 14

Write the chemical formula for Iron (III) oxide.

Answer 14

Fe2O3

Question 15

Write the chemical formula for Calcium oxide.

Answer 15

CaO

Question 16

Write the chemical formula for Magnesium nitride.

Answer 16

Mg3N2

Question 17

Write the chemical formula for Phosphorous pentachloride.

Answer 17

PCl5

Question 18

An ionic salt is dissolved in water and the resulting solution cools. What transformation in energy has occurred?

a) chemical energy was converted to thermal energy
b) thermal energy was converted to chemical energy
c) kinetic energy was converted to solar energy
d) radiant energy was converted to thermal energy
e) thermal energy was converted to kinetic energy

Answer 18

b) thermal energy was converted to chemical energy

Question 19

A final step in the synthesis of aluminum oxide (Al2O3) from its ore bauxite is the following reaction conducted at 1200 degrees celsius.
2Al(OH)3 —–> Al2O3 + 3H2O
If one obtains 2.5010^5 kg of water from the reaction of 2.5010^6 kg of Al(OH)3, what is the % yield of the reaction?

Answer 19

% yield = actual yield/ theoretical yield * 100%

actual yield= 2.510^5 kg or 1.3810^7 mol of H20

theoretical yield= 3.210^7 mol of Al(OH)3 or 4.8110^7 mol of H2O

% yield= 28.7%

Question 20

If a solution containing 26.98g of mercury (II) perchlorate is allowed to react completely with a solution containing 8.564g of sodium sulfate, how many grams of solid precipitate will form? How many grams of the reactant in excess will remain after the reaction?

Answer 20

Hg(ClO4)2 + Na2SO4 —> HgSO4 + 2NaClO4

limiting reactant (smallest amount between two values):
0.06029 mol HgSO4

solid precipitate: 17.89g HgSO4

excess reactant remaining:
26.98g Hg(ClO4)2 - 24.09g Hg(ClO4)2 = 2.89g Hg(ClO4)2 in excess

Question 21

How many significant figures would the answer to this problem have?
1.012*10^-3 / [(0.022456)(298.3682 - 298.3567)]

Answer 21

= 3.92

3 significant figures

Question 22

The electric charge of a single proton is 1.60*10^-19 C. How many protons would you need in order to have a total of one coulomb of positive charge?

Answer 22

1/ (1.6010^-19 C/proton) = 6.2510^8 protons/C

Question 23

The mass of a single proton is 1.67*10^-27 kg. How many protons would you need in order to have a total of one kilogram of mass?

Answer 23

1/ (1.6710^-27 kg/proton) = 5.9910^26 protons/kg

Question 24

Perform the following calculation and record the answer with the correct number of significant figures.
(6.5-6.22) / 2.81

Answer 24

0.1

Question 25

A farmer wants to capitalize on the amount of sunlight shining on his farm everyday by building a solar power tower. The manufacturer\'s specifications state that the solar tower has 75 heliostats, each with an area of 2.70 m2. If the total amount of solar power falling on each heliostat is 1260.0 W/m2, calculate the percent efficiency of the solar power tower if it only produces 29.3 kW.

Answer 25

Percent efficiency = power output/ power input *100% power output= 29.3 KW or 29 300 W power input= 260 000 W percent efficiency= 11%

Question 26

A farmer wants to capitalize on the amount of sunlight shining on his farm everyday by building a solar power tower. The manufacturer\'s specifications state that the solar tower has 75 heliostats, each with an area of 2.70 m2. If the total amount of solar power falling on each heliostat is 1260.0 W/m2, calculate the percent efficiency of the solar power tower if it only produces 29.3 kW.

Answer 26

Percent efficiency = power output/ power input *100% power output= 29.3 KW or 29 300 W power input= 260 000 W percent efficiency= 11%

Question 27

You have 57.0 mL of a 0.500M stock solution that must be diluted to 0.100M. Assuming the volumes are additive, how much water should be added?

Answer 27

C1V1=C2V2 V2=C1V1/C2 V2=285mL 285mL - 57.0mL = 228mL

Question 28

How many grams of solute are present in 265mL of 0.330M of KBr?

Answer 28

265mL= 0.265L 0.0875 mol of KBr 10.4 g

Question 29

Hydrogen peroxide can be prepared by the reaction of barium peroxide with sulfuric acid according to: BaO2 + H2SO4 ---> BaSO4 + H2O2 How many milliliters of 5.00 M H2SO4(aq) are needed to react completely with 26.1 g of BaO2(s)?

Answer 29

0. 154mol BaO2 0. 154mol H2SO4 0. 154/5 = 0.0308L 30. 8mL of H2SO4

Question 30

Which of the following represent potential energy? a) candy bar b) rowing a boat c) a ball rolling down a hill d) a stretched rubber band e) wind f) a roller coaster at the top of a hill

Answer 30

a) candy bar d) a stretched rubber band f) a roller coaster at the top of a hill

Question 31

If 100.0mL of 0.499M Na2SO4 are added to 100.0mL of 0.915M of Pb(NO3)2, how many grams of PbSO4 can be produced? Na2SO4 + Pb(NO3)2 ---> 2NaNO3 + PbSO4

Answer 31

0. 0499mol of Na2SO4 0. 0915mol of Pb(NO3)2 *make a table with initial moles, change in moles, and end result* find the limiting reactant: Na2SO4 is the limiting reactant 0.0915 mol of Na2SO4 is needed to react completely with 0.0915mol of Pb(NO3)2, but there's only 0.0499 mol of Na2SO4 added. 15.1g of PbSO4

Question 32

Name the compound: | H2SO4

Answer 32

sulfuric acid

Question 33

Name the compound: | MnO4-

Answer 33

permanganate ion

Question 34

Name the compound: | NCl3

Answer 34

nitrogen trichloride

Question 35

Name the compound: | P4O6

Answer 35

tetraphosphorus hexoxide

Question 36

Name the compound: | BrCl

Answer 36

bromine monochloride

Question 37

Name the compound: | SF4

Answer 37

sulfur tetrafloride

Question 38

Name the compound: | ClO2

Answer 38

chlorine dioxide

Question 39

Name the compound: | BaO2

Answer 39

barium peroxide

Question 40

Zinc reacts with hydrochloric acid according to the reaction equation: Zn + 2HCl ---> ZnCl2 + H2 How many milliliters of 2.00M HCl are required to react with 6.85g of an ore containing 44.0% Zn by mass?

Answer 40

0. 0461 mol of Zn 0. 0922 mol HCl 0. 0922 / 2 = 0.0461 L 46. 1 mL of HCl