Chapter 4
a) What is the charge and mass of an electron? Proton? Neutron?
b) What is an isotope?
a) Electron: - charge, ~0 amu
Proton: + charge, ~1 amu
Neutron: no charge, ~1 amu
b) atoms of the same element (same # of protons) but with different # of neutrons (therefore have different mass numbers)
Determine the number of protons, neutrons, and electrons in 27Al3+, 55Co3+, and 23Na+
(you will need a periodic table)
27Al3+: 13, 14, 10
55Co3+: 27, 28, 24
23Na+: 11, 12, 10
How many CO2 molecules are in 0.352 moles of CO2?
2.12 x 1023 molecules
What is STP?
The standard temperature is 273 K (0° Celsius or 32° Fahrenheit) and the standard pressure is 1 atm pressure.
A 2.00L mixture of helium, nitrogen, and neon has a total pressure of 815 mmHg at a temperature of 255K. If the partial pressure of helium is 201 mmHg and the partial pressure of nitrogen is 351 mmHg, what mass of neon is present in the mixture?
0.667g
An element has two isotopes: Isotope A has a mass of 10 amu and an abundance of 75%, and Isotope B has a mass of 11 amu and an abundance of 25%. What is the average atomic mass of the element?
(10×0.75) + (11×0.25)=7.5+2.75=10.25amu
Write the ionic formula of the compound formed between Magnesium and oxygen.
Write the ionic formula of the compound formed between Aluminum and Sulfur.
(you will need a periodic table)
MgO
Al2S3
How many grams are in 5.62 × 1019 particles of
carbon tetrafluoride?
0.00822 g CF4
A scuba tank contains O2 and He gases and has a total pressure of 1200 mmHg. What is the partial pressure of O2 gas if the partial pressure of He is 1.125 atm? (give answer in mmHg)
345 mmHg
What species are present when K3PO4(s) dissolves in water?
K+(aq) and PO4 3−(aq) ions
What are the sublevels identified as?
What are their shapes?
How many orbitals does each sublevel have?
And how many electrons can each sublevel hold?
s (sphere)- 1, 2
p(dumbbell)- 3, 6
d(2 dumbbell)- 5, 10
f- 7, 14
Name the following ionic/molecular compounds: (you will need a periodic table)
FeCl3
Co(NO3)2
What do you know has to be in the above compounds?
N2O4
SF6
What do you know has to be in the above compounds?
Iron (III) Chloride
Cobalt (II) Nitrate
Roman Numerals need to be present because the transition metals have multiple charges!
dinitrogen tetroxide
Sulfur hexafluoride
We need the prefixes for molecular compounds!
The density of ethanol is 0.789 g/mL. How much will 1250 mL of ethanol mass in grams?
986 g
A quantity of Ne gas that was originally held at 3.80 atm pressure in a 1.00 L container at 26.0°C is transferred to a 10.0 L container at 20.0 °C. What is the pressure (in atm) of Ne in the new container ?
0.372 atm
At 30 C, the solubility of NO is 6 g per 100 g of water. Identify the following solution as either saturated or unsaturated. Explain.
60 g NO added to 200 g of water at 30 C.
24 g NO added to 300 g of water at 30 C.
saturated, saturated
Draw the orbital diagram for Fluorine.
Draw the orbital diagram for Lithium.
What do we have to remember when drawing orbital diagrams?
↑↓ ↑↓ ↑↓↑↓↑
↑↓ ↑
- That arrows in the same orbital are never going the same direction (i.e. you will never have 2 up or down arrows in one box)
Is Barium Carbonate soluble or insoluble in water?
Which rule did you use?
insoluble, 5
If 3.00 moles of CO and 5.00 moles of H2 are the initial reactants, how many grams of methanol (CH3OH) can be produced? (hint: you need to find molar mass)
80.1 g
A gas takes up a volume of 17 liters, has a pressure of 2.3 atm, and a temperature of 299 K. If I raise the temperature to 350 K and lower the pressure to 1.5 atm, what is the new volume of the gas?
30.5 L
Is RbNO3 soluble or insoluble in water?
Which rule did you use?
Soluble, 2
Write the electron configuration for Mg (magnesium).
Write the electron configuration for Si (silicon).
Mg= 1s² 2s² 2p⁶ 3s²
Si= 1s² 2s² 2p6 3s² 3p²
Given this complete formula equation, write the net ionic equation.
2KCl (aq) + Pb(NO3)2 (aq) -> 2KNO3 (aq) + PbCl2 (s)
2Cl- (aq) + Pb2+ (aq) -> PbCl2 (s)
According to the reaction given below, how many grams of solid Fe(OH)2 is formed when 175 mL of 2.27 M aqueous LiOH reacts with excess aqueous FeCl2? (Note: Molar Mass of Fe(OH)2 is 89.859 g/mol)
FeCl2(aq) + 2 LiOH(aq) → Fe(OH)2(s) + 2 LiCl(aq)
What is the percent yield if 15 grams is actually produced?
17.8g
84.1%
A gas exerts a pressure of 685 mmHg and has a temperature of 245 K. What is the new pressure of this gas, in atm, if the temperature is increased to 655 K? Volume and the amount of the gas stay constant.
2.41
Predict whether a precipitate will form as a result of this reaction: NaOH + K2CrO4 → 2KOH + Na2CrO4
no precipitate will form