Chapter 1
Perform the calculation and report the answer with correct significant figures: 0.0045 × 200
0.9
Identify the following element:
6529X
Cu
How many grams are in 3.2 moles of CaCl₂?
360g
Determine the oxidation state of each element in the compound K₂Cr₂O₇.
K: +1
Cr: +6
O: -2
How many moles of O2 will react with 4.28 moles of Al to form 2Al2O3?
4Al + 3O2 → 2Al2O3
3.21 mol O2
Perform the calculation and report the answer with correct significant figures: 100.0 + 23.45
123.5
What is the percent by mass of hydrogen in ethanol, C₂H₆O?
13.1%
How many oxygen atoms are in 1.0 moles of calcium nitrate, Ca(NO₃)₂?
3.6 * 1024 oxygen atoms
Balance the chemical equation:
___FeCl3(s) + ___H2O(l) →___Fe(OH)3(s) + ___HCl(aq)
FeCl3(s) + 3H2O(l) → Fe(OH)3(s) + 3HCl(aq)
Calculate the mass (grams) of hydrogen gas that can be produced by the electrolysis of 25.0 kg of water.
2H2O(l) --> 2H2(g) + O2(g)
2800g
Perform the calculation and report the answer with correct significant figures: (100.0−99.85) × (0.50 ÷ 2.345)
0.03
How many protons, electrons, and neutrons are present in an atom of Br-81?
35 protons, 35 electrons, and 46 neutrons
Calculate the percent composition of nitrogen in (NH₄)₂SO₄.
21.2%
In the following reaction, identify the oxidizing agent and the reducing agent:
Zn(s) + Cu2+(aq) → Zn2+(aq) + Cu(s)
Cu2+: oxidizing agent
Zn: reducing agent
The combustion of ethanol, C₂H₅OH, is represented by the following balanced equation:
C2H5OH + 3O2 → 2CO2 + 3H2O
If 0.600 mol of O₂ is combined with 1.200 mol of ethanol, how many moles of CO₂ can be produced?
0.400 mol CO2
Express 3.20×10−4 kilometers in nanometers (nm)
3.20 * 108 nm
Answer the questions below for the species:
3517 Cl-
a) How many protons does this atom have?
b) How many neutrons does this atom have?
c) How many electrons does a neutral atom have?
17 protons, 18 electrons, and 18 neutrons
A compound is found to contain 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen by mass.
What is the empirical formula of the compound?
CH2O
Predict whether a reaction will occur when the following solutions are mixed:
AgNO₃(aq) + NaCl(aq) →
AgNO₃(aq) + NaCl(aq) → AgCl(s) + NaNO3(aq)
yes, a reaction will occur
Calculate the moles of reactants and products present after the reaction of 0.300 mol SO₂ with 0.500 mol O₂ is complete.
2SO2 + O2 → 2SO3
SO2: O moles
O2: 0.350 moles
SO3: 0.300 moles
A substance has a density of 1.20 g/mL. If you have 0.250 L of it, what is its mass?
300. g
Calculate the atomic mass of chlorine, given that chlorine has two naturally occurring isotopes:
³⁵Cl, mass = 34.9689 g/mol, natural abundance = 75.77%
³⁷Cl, mass = 36.9659 g/mol, natural abundance = ?
35.45 g/mol
A compound has an empirical formula of CH₂O and a molar mass of 180 g/mol. What is the molecular formula of the compound?
C6H12O6
Write the net ionic equation for the following reaction:
HNO2(aq) + KOH(aq) → KNO2−(aq) + H2O(l)
HNO2(aq) + OH- (aq) → NO2-(aq) + H2O(l)
Suppose that 10.0 g N₂ reacts with 3.00 g H₂ to produce 12.0 g NH₃.
Determine the percent yield of ammonia from this reaction.
N2(g) + 3H2(g) → 2NH3(g)
98.7%