Exam #1
Complete the following calculation, keeping the correct number of significant figures:
10.03 - 1.11 - 8x10-3
8.91
Which of the following is/are true? Select all that apply.
a.) Ga2O3 is digallium trioxide
b.) NO is nitrogen monoxide
c.) ClO3 is chlorine trioxide
d.) N2O5 is dinitride pentoxide
b and c
What mass in grams of H2O is produced from 44.5 grams of O2 gas using the reaction below?
4 NH3(g) + 3 O2(g) → 2 N2(g) + 6 H2O(g)
50.12 g H2O
Write the molecular formula for nitrate, phosphate, chlorate, carbonate, and sulfate.
NO3-, PO43-, ClO3-, CO32-, SO42-
A fictional element has 3 naturally occurring isotopes. The first has a mass of 57.241 amu and an abundance of 24.43%. The second has a mass of 62.223 amu and an abundance of 27.28%. The third has a mass of 65.646 amu. Calculate the atomic mass of the fictional element, giving your answer to 4 significant figures.
62.66 amu
Indicate the strongest intermolecular force present for the following substance: XeF4
a.) Dispersion forces
b.) Dipole-dipole forces
c.) Hydrogen bonding
d.) Ion-dipole forces
a.) Dispersion forces
You would like to actually produce 73.7 grams of aluminum oxide using the reaction that follows, which has a 63.1% yield. What mass in grams of oxygen gas is needed? 3 O2(g) + 4 Al(s) → 2 Al2O3(s)
55 g O2
Write the molecular formula for cyanide, peroxide, and acetate.
CN-, O22-, C2H3O2-
An engineering firm uses a custom unit of distance for a client called "pules" when working with a metal alloy. The metal alloy has a density of 8.12 g/cm3. What volume in pules3 (cubic pules) of this alloy will 45.9 kg occupy? Give your answer to 3 significant figures. 1 m = 25.2 pules
90.5 pules3
Determine the molecular geometry for each compound.
a.) BeF2
b.) SF2
c.) CBr4
d.) BrF3
a.) linear
b.) bent
c.) tetrahedral
d.) t-shaped
If 79.3 mL of 0.311 M potassium nitrate is added to 18.6 mL of 0.527 M barium nitrate, find the molarity of nitrate ions in the final solution.
0.454 M
You're planning on driving across country with 5 friends for spring break to a city 682 miles away (one way). Your van averages 17.3 miles per gallon. The average cost for gasoline is $3.21 per gallon. How much will each person need to pay toward gas for the trip (both there and back), assuming the cost is evenly divided between you and your 5 friends? Give your answer to the nearest penny.
$42.18 per person
Calculate the de Broglie wavelength in pm of a xenon gas atom (Chemical Symbol: Xe) moving 308 m/s. Give your answer to 3 significant figures.
9.87 pm
How many molecules are contained in 4.63 g C2H2? Give your answer to 3 significant figures.
1.07 x 1023 molecules
A metal ball with a mass of 248 g and specific heat capacity of 0.268 J/(g °C) releases 3.165 kJ of thermal energy to its surroundings. If the final temperature of the ball is 240 °C, find the initial temperature.
287.62 °C
What is the mass in µg of 9.18 x 1016 atoms of iodine (Chemical symbol: I)? Give your answer to 3 significant figures.
19.3 µg
An electron in a hydrogen atom transitions from n=3 to n=1. Find the frequency of the emitted photon in Hz. Give your answer to 3 significant figures.
2.92 x 1015 Hz
Calculate the total number of atoms in 83.8 ng C51H72N5O13. Give your answer to 3 significant figures.
7.39 x 1015 atoms
A sample of gas in a cylinder equipped with a piston absorbs thermal energy from an external flame and expands against a constant external pressure of 2.73 atm from 0.439 L to 1.895 L. If the internal energy of the gas sample increases by 121 J during this process, find heat in J for the gas sample. 101.3 J = 1 L atm
524 J
Write the ground-state electron configuration for the Cu+ ion.
1s2 2s2 2p6 3s2 3p6 3d10