Unit 2 Practice Problems

Name:______Date:______

Unit 2 Practice Problems

1.  Complete the following chart.

Element

/ Atomic Number / Atomic Mass / Protons / Electrons / Neutrons / Charge / Symbol
Iron / 26 / 56 / 0
Oxygen / 8 / 16 / 10
Neon / 10 / 10 / 0
Magnesium / 12 / 11 / +2

2.  How many protons, neutrons, and electrons are there in a neutral atom of sodium?

P = N = E =

3.  If you obtained an isotope of the atom described in the previous question, how would this change the number of protons, neutrons, and electrons?

______

4.  Use the information shown below to calculate the average atomic mass of Silicon.

Silicon – 28 92.23 % Abundance

Silicon – 29 4.68 % Abundance

Silicon – 30 3.09 % Abundance

5.  Name the following compounds. (Don’t forget to identify them as ionic or molecular!)

Na2SO4 ______

XeF6 ______

Na2O ______

PCl3 ______

Al2O3 ______

NO2 ______

K2SO4 ______

N3O8 ______

Sr(NO3)2 ______

NH4NO2 ______

CoBr3 ______

CuSO4 ______

6.  Write the chemical formulas for each of the following compounds.

Aluminum Chloride ______

Diphosphorus Monosulfide ______

Calcium Hydroxide ______

Barium Acetate ______

Potassium Carbonate ______

Vanadium (V) Phosphide ______

Phosphorus Pentachloride ______

Ammonium Oxide ______

Carbon Tetrachloride______

Nickel(II) Sulfate ______

Trisulfur Diphosphide ______

Ammonium Phosphate ______

Oxygen Difluoride ______

Magnesium Nitrate ______

Manganese (VII) Oxide ______

7.  Balance and classify each of these chemical expressions.

____Al2O3  ____Al + ____O2

____Al + ____S8  ____Al2S3

____H 3PO4 + ____Mg(OH)2  ____Mg3(PO4)2 + ____H2O

____ CH3OH + ____ O2  ____ CO2 + H2O

____ Cl2 + ____ MgO  ____ MgCl2 + ____ O2

____ ZnBr2 + ____ AgNO3  ____ Zn(NO3)2 + ____ AgBr

8.  Convert each of the following reactions into a balanced chemical equation.

a.  Acetone (C3H6O) burns in oxygen to yield carbon dioxide and water.

b.  Copper is added to magnesium chloride to yield magnesium and copper(II) chloride.

c.  Calcium metal reacts with oxygen to produce calcium oxide.

d.  Potassium carbonate decomposes into potassium oxide and carbon dioxide.

e.  Iron(II) nitrate mixes with aluminum chloride to yield iron(II) chloride and aluminum nitrate.

9.  How much energy, or heat, is required to heat 75 mL of water from 25°C to 57°C? The heat capacity of water is 4.184 J/g°C.

10.  What is the mass of a piece of nickel metal if it is heated to 100.0°C and placed into 250.0 grams of water at 21.52 °C in a calorimeter with a heat capacity of 95.3 J/K and the temperature stabilizes at 25.82 °C?

11.  An unknown metal is heated to 100°C and then placed in a calorimeter. The 175 mL of water in the calorimeter rises from 22.3°C to 36.0°C. The amount of heat transferred is 309.1 Joules. Using the chart below, identify the metal.

Metal / Specific Heat Capacity (J/g°C)
Gold / 0.129
Lead / 0.160
Iron / 0.444
Aluminum / 0.900