Naming
When do we use Roman numerals in naming
with transition metals
1. moles of sample
2. molecules in sample
3. atoms in sample
1. 0.0543 moles
2. 3.27 X 10^22 molecules
3. 3.92 X 10^23 atoms
which of the following statements are true?
a. at constant temp., the lighter the gas molecules, the faster the average velocity of the gas molecules
b. at constant temp., the heavier the gas molecules, the larger the average kinetic energy of the gas molecules
c. a real gas behaves most ideally when the temp. is low and the pressure is high
d. at least two of the above are true
e. none of the above are true
a. lighter the molecule is the faster the average velocity of the gas molecules
which of the following statements are true?
a. a spoonful of sugar is a mixture
b. only elements are pure substances
c. air is a mixture of gases
d. gasoline is a pure substance
e. compounds can be broken down only by chemical means
c, e
Where is the best burger on campus?
Joe's
When do we use prefixes
with 2 non-metals
empirical formula is X2YZ3
the atomic masses of X, Y, and Z are 41.2, 57.7 and 63.9 respectively
find percentage composition by mass of the compound
24.8% X, 17.4% Y, 57.8% Z
if 10 g of liquid helium at 1.7 K is completely vaporized, what volume does the helium occupy at STP?
56 L He
which of the following describes a chemical property?
a. the density of iron is 78.7 g/mL
b. platinum wire glows red when heated
c. an iron bar rusts
d. aluminum is a silver-colored metal
c- rusting
What is Madi's cat's name?
Zoey
what's the formula for Magnesium Acetate
Mg(C2H3O2)2
calculate the number of grams of cobalt that contain the same number of atoms as 2.24 g of iron
2.36 g Co
if 0.214 mole of argon gas occupies a volume of 652 mL at a particular temperature and pressure, what volume would 0.375 mole of argon occupy under the same conditions?
1.14 L
a helium tank contains 25.2 L of helium at 8.50 atm. determine how many 1.5 L balloons at 755 mm Hg can be inflated with the gas in the tank, assuming the tank will also have to contain He at 755 mm Hg after the balloons are filled (cannot completely empty the tank). the temperature is 25 C in all cases.
125 balloons
What time should you get to the exam
6:45 pm
what's the name for V(SCN)3
Vanadium (III) Thiocyanate
if you have equal moles sample of nitrogen dioxide and fluorine gas, which of the following must be true
a. number of molecules in each sample is the same
b. number of atoms in each sample is the same
c. masses of the sample are the same
d. 6.022X10^23 molecules are present in each sample
a. number of molecules in each sample are the same
consider the following chemical equation:
N2 (g) + 3 H2 (g) --> 2 NH3 (g)
what volumes of nitrogen gas and hydrogen gas, each measured at 11 C and 0.998 atm, are needed to produce 5 g of ammonia?
0.967 atm
which of the following are true:
a. if the number of moles of a gas is doubled, the volume will double, assuming constant pressure and temp.
b. if the temp. increases from 25 to 50 C, the volume of gas would double, assuming the pressure and moles are constant
c. the device that measures atm is called a barometer
d. if the volume of a gas decrease by 1/2, then the pressure would double, assuming that moles and temp. are constant
a, c, d
Do you know where your exam is tonight
I hope so
what's the name and formula for a compound consisting of 2 moles nitrogen and 6 moles chlorine. write both the empirical and molecular.
N2Cl6 = dinitrogen hexachloride
empirical
NCl3 = nitrogen trichloride
how many anions are there in 5 g of calcium bromide
3.01 X 10^22 anions (Br- ions)
a large flask with a volume of 936 mL is evacuated and found to have a mass of 134.66 g. it is then filled to a pressure of 0.967 atm at 31 C with a gas of unknown molar mass and then reweighed to give a new mass of 135.87 g. what is the molar mass of this gas?
33.3 g/mol
which of the following are true?
a. 40 Ca+2 contains 40 protons and 18 electrons
b. Rutherford created the cathode-ray tube and was the founder of the charge-to-mass ratio of an electron
c. an electron is heavier than a proton
d. the nucleus contains protons, neutrons and electrons
a
Best ice cream in Champaign
Jarlings