Chapter 1 and 2
Qualitative vs. Quantitative
Give an example of each
Qualitative- description in words (red, cloudy, hot)
Quantitative- description in numbers (mass is 12 grams)
If an element (assume that it is neutral) has a mass number of 45 and an atomic number of 20: what is the element, number of protons and number of neutrons?
Ca, p=20, n=25, e=20
Balance:
NaNO₃ (s) + H₂SO₄ (aq) → Na₂SO₄ (s) + HNO₃ (aq)
C6H6+O2→CO2+H2O
2 NaNO₃ (s) + H₂SO₄ (aq) → Na₂SO₄ (s) + 2 HNO₃ (aq)
2 C6H6+15 O2→ 12 CO2+6 H2O
If you start with 5.000 grams of methane (CH₄), how many grams of carbon dioxide (CO₂) will be produced?
13.72g
How much energy is needed to raise the temperature of 120.g of water from 15.0°C to 85.0°C? (Specific heat of water = 4.18 J/g·K)
35,112J
How many atoms of H are in 3.2 mols of H2 gas?
Avogadro's number: 6.022 x 1023
3.85 x 1024 atoms
Calculate the molar mass of C6H12O6
180.159 g/mol
What is the combustion of C8H18?
2C8H18+25O2→16CO2+18H2O
A sample of an unknown hydrocarbon burns completely and produces 0.500 g of CO₂ and 0.200 g of H₂O. Determine the empirical formula of the hydrocarbon.
CH2
How many milliliters of 0.150 M phosphoric acid (H₃PO₄) are required to neutralize 55.0 mL of 0.0400 M sodium hydroxide (NaOH)?
4.89 ml
Give me an example of each of the following:
homogenous mixture
heterogenous mixture
pure substance (compound)
pure substance (element)
homogenous mixture- Milk
heterogenous mixture- iced tea
pure substance (compound)- Distilled H2O, salt
pure substance (element)- diamond, Na, Cl2
Element W has three isotopes:
Isotope 1: Mass = 50.00 amu, Abundance = 10%
Isotope 2: Mass = 52.00 amu, Abundance = 60%
Isotope 3: Mass = 54.00 amu, Abundance = 30%
Calculate the atomic weight of element W.
52.40 amu
Determine if the following are strong, weak, or nonelectrolyte:
MgO
CH4
HI
NH3
NaOH
ionic: strong electrolyte
molecular: non-electrolyte
strong acid: strong electrolyte
molecular: weak electrolyte
strong base: strong electrolyte
What is the concentration of a solution prepared by diluting 50.0 mL of 6.0 M hydrochloric acid (HCl) to a total volume of 400.0 mL?
.75M
C₂H₆(g)+O₂(g)→CO₂(g)+H₂O(l)
Given ΔHf values; Calculate ΔHr using the formula:
i. ΔHf for C₂H₆(g)=−84.68 kJ/mol
ii. ΔHf for CO₂(g)=−393.5 kJ/mol
iii. ΔHf for H₂O(l)=−285.8 kJ/mol
ΔHr∘= −3115.84kJ/mol
How many sigfigs are in the following:
.00034
60
300.
.0007080
4.08 x 10-4
.00034- 2
60- 1
300.- 3
.0007080- 4
4.08 x 10-4- 3
A compound contains 40.0% Carbon, 6.7% Hydrogen, and 53.3% Oxygen by mass. What is the empirical formula of the compound?
What is the molecular formula if the mass is 90.1g.
CH2O
C3H6O3
Write the net ionic equation:
Pb(NO₃)₂(aq)+2KI(aq)-->
Pb⁺²(aq)+2I⁻(aq)→PbI₂(s)
You mix 25.0g of sodium bicarbonate (NaHCO₃) with 15.0g of acetic acid (CH₃COOH).
NaHCO₃(s) + CH₃COOH(aq) → CH₃COONa(aq) + CO₂(g) + H₂O(l)
What is the limiting reagent?
What mass of carbon dioxide is produced?
CH₃COOH
11.0g CO2
Calculate ΔHr for the reaction: CaO+CO₂→CaCO₃, ΔH=?
Given:
i. Ca+1/2O₂→CaO, ΔH=−635.1 kJ
ii. C+O₂→CO₂, ΔH=−393.5 kJ/mol
iii. Ca+C+3/2O₂→CaCO₃, ΔH=−1206.9 kJ/mol
-178.3 kJ/mol
What is the length in cm of 34.00 g of lead (density = 11.34 g/cm3) with two measured
dimensions of 0.60 cm and 0.44 cm?
11.36cm
Name the following:
CaSO4
N2O4
Fe2O3
Na2SO4 x 3H2O
Calcium sulfate
Dinitrogen tetroxide
Iron (III) Oxide
Sodium sulfate trihydrate
What are the oxidation numbers of the following:
H2SO4
KMnO4
Fe2O3
H= +1; S= +6; O= -2
K= +1; Mn= +7; O= -2
Fe= +3; O= -2
Ethylene (C₂H₄) reacts with water to produce ethanol (C₂H₅OH). You have 50.00g of ethylene if the actual yield is 70.00g of ethanol, what is the percent yield?
85.24%
A 200 g sample of aluminum metal at 90.0 °C is placed into 300 g of water at 22.0 °C in a calorimeter. When the system reaches thermal equilibrium, the temperature of the water in the calorimeter is 25.5 °C. Assume the calorimeter is perfectly insulated. The specific heat of water is 4.184 J/g·K. a. What is q for the water? What amount of heat was transferred from the aluminum? Determine the specific heat of aluminum from this experiment?
4393.2 J
-4393.2 J
.341 J/gC