Chemistry 3a Test 2

24 July 2022
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question
How many atoms are in 1.50 moles of fluorine gas?
answer
fluorine is a diatomic molecule so multiply by 2. (2)(1.50 mol)(6.02x10^23 atoms/mol) = 1.81x10^24 atoms
question
How many atoms are in 5.80 moles of Helium?
answer
5.80 mol He * 6.022*10^23 atoms He/ 1 mol He. This cancels out moles, leaving 3.49*10^24 atoms He.
question
Mass is used as a method of counting atoms.
answer
true
question
The chemical formula clearly indicates the relationship between the mass of each element in the formula.
answer
false
question
one mole of oxygen has mass of ___ g
answer
When you are discussing oxygen as the free, uncombined element, then you are discussing oxygen gas, the formula of which is O2 and the molecular weight of which is 32. (which, as you well know, comes from 16 x 2).
question
The mass of one mole of carbon dioxide is ________ g.
answer
44.01
question
What is the molar mass of aluminum sulfate?
answer
342.2 g/mol
question
Calculate the molar mass of ammonium carbonate.
answer
96.09 g/mol
question
One mole of (NH4)2HPO4 contains how many moles of hydrogen atoms?
answer
9
question
The chemical formula CuBr2 indicates that this compound is composed of 1 gram of copper and 2 grams of bromine.
answer
false
question
One mole of lead(II) nitrate contains six moles of oxygen atoms.
answer
true
question
one mole of ammonium nitrate contains
answer
2 moles of nitrogen
question
One mole of ammonium nitrite contains:
answer
4moles hydrogen 2 moles of oxygen 2 moles of nitrogen
question
One mole of potassium sulfate contains:
answer
4 moles oxygen
question
How many moles of carbon are in 3.5 moles of calcium carbonate?
answer
3.5 1 mole of CaCO3 contains one mole of Calcium, one mole of Carbon, and 3 moles of Oxygen. the subscripts indicate the number of moles. so if you have 3.5 moles of CaCO3, then you also have 3.5 moles of C
question
molar mass of calcium nitrate
answer
Calcium Nitrate is Ca(NO3)2. = (1 x Ca40) + (2 x N14) + (6 x O16) = 164grams per mole (164g/mol).
question
How many molecules of sulfur trioxide are in 78.0 grams?
answer
5.87x10^(23) Molar mass SO3 = 32.066+(15.99*3) = 80.036g/mol 78.0/80.036*6.022*10^23 = 5.86*10^23 molecules.
question
How many moles of fluorine are in 3.2 moles of xenon hexafluoride?
answer
XeF6 is Xenon hexafluoride.... 6 atoms F per 1 molecule XeF6.. right? 6 moles F per 1 mole XeF6 so that... 3.2 moles XeF6 x (6 mole F / 1 mole XeF6) = 19.2 moles F
question
The higher the principal quantum number, the lower the orbital energy.
answer
False
question
The possible values for the principal quantum numbers are: n = 0, 1, 2, 3, 4.
answer
False
question
The subshells s, p, d, and f all have the same energy as long as they are in the same principal shell.
answer
False
question
The ground state is when an electron in an atom is excited into the lowest possible vacant orbital.
answer
False
question
When an aluminum atom reacts so as to attain a noble gas electron configuration
answer
1s2 2s2 2p6
question
Which of the following neutral elements has the same electron configuration as the bromide ion, Brโˆ’?
answer
Krypton