Exam 1
Substances A and B are the same mass and at the same initial temperature. When they are heated, the final temperature of A is 55 °C higher than the temperature of B. What does this tell you about the specific heats of A and B?
The specific heat of A must be less than the specific heat of B
Write the name Fe(HCO3)3
Iron (III) hydrogen carbonate
The solubility of KI at 20 degrees is 70 solute/100 g H20. Is 245 grams/ 340 grams water saturated?
Yes
Determine the pH
[H3O+]=2.0x10-8
acidic or basic?
pH=7.7, basic
Draw the oribital diagram of argon
...
Classify each of the following as a pure substance or a mixture:
baking soda
a blueberry muffin
ice
zinc (Zn)
trimix (oxygen, nitrogen, and helium) in a scuba tank
1. pure
2. mixture
3.pure
4.pure
5. mixture
Arrange in order of increasing electronegativity
Se, Ca, O
Ca, Se, O
How would the following affect the rate of reaction?
a. adding SO2
b. adding catalyst
c. decreasing O2
2SO2 (g)+ O2(g) > 2SO3 (g)
a.increase
b.increase
c.decrease
Which of the following represents a buffer system?
NaOH and NaCl
H2CO3 and NaHCO3
HF and KF
KCl and NaCl
b and c
Strongest intermolecular force KCl
ionic
What is the density (g/mL) of a sample of mineral oil if 250 mL has a mass of 0.23 kg?
.92 g/mL
3NO2 + H2O > 2HNO3 + NO
How many grams of NO are produced from 15.8 grams of H2O
26.3 grams of NO
How many grams of H2O are formed from the reaction of 15g of H2S AND 25.0grams of O2?
2H2S + 3O2 > 2SO2 + 2H2O
7.93 g H2O
Complete and balance the equation for each of the following reactions:
HBr + ZnCo3 >
HCl + Zn (s)
a.2HBr +ZnCo3 > CO2 (g) + H2O (l) + ZnBr2
b. 2HCl +Zn (s) >H2 (g) +ZnCl2(aq)
Indicate the postive and negative side of the dipole and draw the arrow
P and Br
arrow towards Br
There are two naturally occurring isotopes of boron. The isotope has a mass of 10.01 amu with an abundance of 19.80%, and the isotope has a mass of 11.01 amu with an abundance of 80.20%. Calculate the atomic mass for boron using the weighted average mass method.
10.81 amu
Predict angle, shape, geometry of NO2+
angle:180 degrees
shape:linear
geometry:linear
Calculate Kc, of .30 M of H2, .17 M I2 and 1.66 M HI
H2 + I2 > 2HI
54
Identify the conjugate acid-base pairs in each of the following equations and whether the equilibrium mixture contains mostly products or mostly reactants:
NH3(aq)+HNO3(aq)><NH4+(aq) +NO3-(aq)
HNO3/NO3- and NH4/NH3 mixture contains mostly products
Describe the effect of change on the equilibrium
2CH4O (g) + 3O2 g>< 2CO2 (g) + 4H2O g + 1450 KJ
a. Increasing volume
b.adding CO2
c. removing O2
a. product, more mols of g in products
b. reactants
c. reactants
The price of 1 lb of potatoes is $1.75. If all the potatoes sold today at the store bring in $1420, how many kilograms of potatoes did grocery shoppers buy?
368 kg
2H2O2 > 2H2O + O2
How many moles of H2O2 are needed to produce 3.00 moles H20
3.00 moles of H2O2
A sample of Ar gas has a volume of 5.40 L with an unknown pressure. The gas has a volume of 9.73 L when the pressure is 3.62 atm, with no change in temperature and amount of gas. What was the initial pressure, in atmospheres, of the gas?
6.52 atm
One of the most acidic lakes in the United States is Little Echo Pond in the Adirondacks in New York. Recently, this lake had a pH of 4.2, well below the recommended pH of 6.5.
What is [H3O+] and [OH-] of Little Echo Pond?
[H3O+]=6x10-5
[OH-]=2x10-10
Solution A has a pH of 4.5, and solution B has a pH of 6.7
Which solution is more acidic?
What is the [H3O+] in solution A?
solution A is more acidic
3.2x10-5