CST REVIEW 2

Question 1

Balance the following equation:

FeCl₃ + NaOH –> Fe(OH)₃ + NaCl

Answer 1

FeCl₃ + 3NaOH –> Fe(OH)₃ + 3NaCl

Question 2

If a chemical reaction is at equilibrium, which direction will the reaction shift if a product is removed as it forms?

Answer 2

shift right

Removing a product as it forms creates a “hole” and has to be filled

Question 3

What are the products of a neutralization reaction?

Answer 3

water and a salt

Question 4

If methane gas reacts with 50 grams of oxygen gas in a combustion reaction and 94 grams of products are produced, how many grams of methane were used in the beginning?

Answer 4

44 grams

(conservation of mass)

mass of reactants = mass of products

94 - 50 = 44g

Question 5

What are the 5 types of chemical reactions?

Answer 5

Synthesis

Decomposition

Combustion

Double Displacement

Single Displacement

Question 6

A compound is made of magnesium and oxygen that has a molar mass of 41 g/mole. How many grams would

9.03 x 10²³ formula units weigh?

Answer 6

61.5 grams

1 mole = 6.02 x 10²³

1.5 moles = 9.03 x 10²³

41 + (41x .5) =61.5g

Question 7

What type of compound is P₂O₅, diphosphorus pentoxide?

Answer 7

Molecular- 2 nonmetals

prefixes in name

Question 8

What is the name of CaCl₂?

Answer 8

Calcium chloride

(binary compounds end in -ide)

Question 9

What is 595 K in ^oC?

Question 10

If a 3.0 L container is at a temperature of 375 K and at a pressure of 0.98 atm, what would the equation look like to solve for moles? ( R = 0.0821)

Answer 10

n = PV / RT

(0.98 atm)(3.0L) / (0.0821) (375 K)

Question 11

Where are the floowing things located on the periodic table?

1) most reactive metal
2) most reactive nonmetal
3) largest atom of period 4
4) largest atomic number in the halogens
5) transition metal block

Answer 11

1) Cs or Fr
2) F
3) K
4) I (53)
5) b block

Question 12

How many valence electrons does Lead (Pb) have? What does the dot structure look like?

Answer 12

4

.

. Pb .

.

Question 13

What sublevels are filling as you move across the transition metals?

Answer 13

d sublevels

Question 14

What type of particle is missing in the reaction below?

6₃Li + ¹₀ n → _____ + ³₁H

Answer 14

alpha particle

( helium atom)

Question 15

What is the number of protons, neutrons, and electrons of the particle Ba⁺² ?

Answer 15

56 protons

81 neutrons

54 electrons

Question 16

What term is used to describe the following physical processes?

Indicate whether the process is endothermic or exothermic?

1) liquid to solid
2) gas to liquid
3) solid to liquid
4) liquid to gas

Answer 16

1) freezing- exothermic

2 condensation- exothermic

3) melting- endothermic
4) boiling / vaporization- endothermic

Question 17

In the balanced equation

2H_2(g) + O_2(g) –> 2H₂O(l)

If the reaction is at equilibrium, what direction would the reaction shift if you increased the pressure?

Question 18

What is temperature a measure of?

Answer 18

The kinetic energy of the particles

(how fast the particles are moving)

Question 19

A solution is considered this kind of mixture.

Answer 19

Homogeneous mixture (uniform)

Question 20

In the chart above, how much KNO_³ will dissolve in 100g of water at 50^oC?

Answer 20

80 grams

Question 21

Identify whether the following changes are a physical or chemical

1) wood rotting
2) evaporation
3) forest burning
4) ice melting
5) sugar dissolving in water
6) acid reacting with a base

Answer 21

1) chemical
2) physical
3) chemical
4) physical
5) physical
6) chemical

Question 22

If a gas is in a 2.0 L glass container at a pressure of 113.25 kPa, what would happen to the pressure if the temperature is increased?

Answer 22

it would increase

(Volume is constant- glass)

Question 23

What type of reaction does the graph above represent?

How do you know?

what is the sign of H?

Answer 23

ENDOTHERMIC

The products are at a higher energy than the reactants so energy was gained making the chenge in heat +

Question 24

A compound is known to contain Oxygen (16 amu). If the compound has a mass of 100 grams and is was determined that there was 34 grams of oxygen in the sample, what is the percent of oxygen in the compound?

Answer 24

% = part / whole x 100

34 /100 = .34 x 100 = 34% Oxygen in sample

Question 25

If a diver goes deep int the water where the atmospheric pressure becomes 4 atm (he started at sea level), if the volume of a plastic bag was 1.0 Liters when he left the surface, what will the volume be at the new pressure deep in the ocean?

Answer 25

P and V are inversely proportionate….

so if the pressure was quadrupled, then the volume has to be cut in 1/4th.

1 atm (sea level) / 4 = 0.25 L

Question 26

What process does the following reaction represent?

²³⁵₉₂ U –> ¹⁴²₅₆ Ba + ⁹¹₃₆Kr + 3 ¹₀n

Answer 26

Fission

1 atom becoming 2 different atoms in a nuclear reaction

Question 27

H

:

H ·· C ·· H

:

H

1) This structure is a representative of what kind of compound?
2) What do the dots represent?
3) What rules are being followed to make this structure?

Answer 27

1) it is a molecule made of nonmetals covalently bonded together (electron pairs are shared)
2) the dots represent the electrons in a covalent bond
3) Octet rule: Carbon needs 8 valence electrons to become stable

Question 28

How many significant digits are in the following measurements?

a) 0.0043700 moles
b) 1204020000 km
c) 6.02 x 10²³
d) 40000
e) 0.98000000
f) 8000.0

Answer 28

a) 5 leading zeros do NOT count
b) 6 ending zeros do not count without a decimal
c) 3 all numbers in scientific notation count
d) 1 no decimal in number
e) 8 final zeros with a decimal
f) 5 decimal in number final zeros count

Question 29

How many numbers would be in the answer of the following problem:

2.450 g / 0.85 ml =

Answer 29

2

when multiplying and dividing the answer can contain as many numbers as the measurement with the fewest sig figs

Question 30

Which group of elements has the LOWEST ionization energies (energy required to lose an electron)?

Answer 30

Alkali metals

metals have LOW and nonmetals have HIGH as they do not want to get rid of any of their electrons