Exam 1
What is the difference in a cation and anion?
cation: positive charge
anion: negative charge
What is the trend for electronegativity?
increases up and to the right
What equation should you use with dilution problems?
What does each variable stand for? What are their units?
M1V1 = M2V2
M = concentration (mol/L)
V = volume (L)
How many sig figs are in 0.1230?
4
What is the scientific notation for 0.00004261?
4.261 x 10-5
How many valence electrons are in Xe2+?
6
What intermolecular forces are present in a molecule of ammonia?
dispersion, dipole-dipole, hydrogen bonding
Is CH3F polar or nonpolar?
If it's polar, what is the atom closest to the negative side?
polar
F (more electronegative)
What compound is iodine and calcium most likely to make?
CaI2
Draw the Lewis structure for N22-
2 double-bonded nitrogens, each with 2 lone pairs, and brackets with a 2-
Write the equilibrium constant expression for the following reaction:
2 CuI(s) + I2(aq) → 2 Cu2+(aq) + 4 I-(aq)
don't include solids or liquids in K!
[I-]4[Cu2+]2 / [I2]
What is the concentration of H3O+ of a solution with a pH of 4.57?
2.7 x 10-5 mol/L
How many protons and neutrons are in an isotope of 102Rh?
protons: 45
neutrons: 57
The atmospheric pressure in La Paz, capital of Bolivia, is 0.632 atm. Calculate the atmospheric pressure in mmHg and torr.
480. mmHg
480 torr
You have an endothermic reaction, shown below.
4 NO + 6 H2O → 4 NH3 + 5 O2
What direction will the reaction shift if we lower the temperature? What will happen to the pressure of O2?
shifts to the left
O2 pressure will go down.
Calculate the energy required to heat 824.0 g of ammonia from 54.6°C to 66.9°C. Assume the specific heat capacity of ammonia is 4.70 J/(g·K).
47.6 kJ
How many atoms are in 4 moles of HF?
2.4 x 1024 atoms
Use the equation below. What mass of NH3 is consumed to make 8.76 g of O2?
4 NH3 + 5 O2 → 4 NO + 6 H2O
3.73 g
A chemist makes 400. mL of working solution by adding distilled water to 250. mL of 0.365 M stock solution. What is the concentration of the chemist's working solution?
0.228 mol/L
A chemist dissolves 431 mg of HCl in 150 mL of solution. Calculate the pH of the solution.
(hint: the molar mass of HCl is 36.458 g/mol)
pH = 1.1034