Conversions
Particles, moles, grams OH MY
Particles, moles, grams OH MY
You have 3.4 x 1030 formula units of CaCl2. How many moles of CaCl2 is that?
SHOW YOUR WORK
5.6 X 106 moles or 56,478,841 moles
In a 200 mL volumetric flask, you add 6 moles of NaCl and add water. What's the concentration of the solution you just made?
1000 mL = 1 L
30M
A gas is at a pressure of 4 atm and a volume of 7 L. If the volume is compressed to 4.4 L, what will the new pressure be?
6.4 atm
H2(g) + Cl2(g) --> 2HCl(g)
If 5.7 L of chlorine react with excess hydrogen, how many L of HCl should you expect to be produced?
11.4 L HCl (g)
Which one of these molecular formulas is also its own empirical formula?
S2Cl10 P11Cl4 F18O27Br54 C33H11O22
P11Cl4
How many grams of I2 are in a 17 mole sample?
4314.6 g
You add 70 g of LiBr to 3L of water. What's the molarity of that solution?
0.27 M
mol/L
mol L-1
A gas at 700 K fills up 6 m3 of space. When that gas cools down to 300 K, what volume will it take up?
2.6 m3
6 moles of a gas is taking up 8 L of space. If another gas is in the same conditions (same T and P) and is taking up 10 L of space, how many moles is that sample?
7.5 L
C5H15O10
If you have 15 g of Na, how many atoms of Na is that?
2 step conversion
3.9e23 atoms
Mrs. Onushko needs to make a 1.5 M solution of koolaide. She needs a total volume of 1.5 L. She has a concentrated vat of 4M koolaide available. Describe how she would make her solution.
Mix 562.5 mL (.5625 L) of the stock solution with 937.5 mL (.9375 L) of water
A sample is in a fixed volume container at 60 kPa and 435 K. If the temperature drops to 200 K, what will the new pressure be?
27.6 kPa
A gas is at 70 kPa, taking up 40 mL of space and is 103 degrees C. The pressure is then changed to 80 kPa and the container shrinks to 30 mL of space. What new temperature is the gas at, in degrees C?
T = 322.3 K BUT celcius asked for...
49.3 degrees C
- celcius doesn't make sense! Do you have negative volume? You can't take up negative space.
Kelvin is better about directly relating speed of particles with the volume those gas particles take up. When Kelvin = 0, speed = 0 and volume should =0.
How many atoms of oxygen are in 6g of Ba(BrO3)2?
6 * (1/393.13) * (6/1) * (6.02e23/1) =
5.5e22 atoms O
1) find moles 2) convert to g
43.83 g NaCl
A weather balloon starts it's flight at 1.1 atm, 295 K and is at a volume of 3 L. As it rises into the atmosphere, the pressure decreases to 0.8 atm and the temperature drops to 268 K. What is the volume of the balloon?
3.74 L
8.9 moles of an ideal gas is at 7e5 Pa and 70.4 degrees C. What volume is it taking up? (include units)
0.036 m3
A compound is 26.5% carbon, 2.94% hydrogen and 70.6% oxygen. What is the empirical formula of this compound?
.33 means you need to multiply by 3!
C3H4O6
How many moles of water are in 60 g of CaCl2 . 3H2O?
60 * (1/165.04) * (3/1) =
1.09 mol water
Mr. Longley needs 0.5 L of at 0.2M solution of H2SO4. Describe how he should make this solution from a 6M stock solution.
Please use mL when describing volumes.
Pour 16.7 mL of the stock solution into a 0.5 L volumetric flask. Dilute up to the mark.
OR
Pour 16.7 mL of the stock solution. Add 483.3 mL water.
An unknown amount of an ideal gas fills 50 dm3 of space at 400K at 60 kPa. How many moles of gas is there?
0.90 mol
2C2H6(g) + 7O2(g) --> 4CO2(g) + 6H2O(g)
The above reaction happened at STP. If 20 g of C2H6 was reacted with excess oxygen, what total volume of both products should you expect to be produced?
30.2 L CO2 + 45.3L H2O = 75.5 L total product
Find the percent composition of EVERY atom in:
Ca3(PO4)2
Ca = 38.8%
P = 20.0 %
O = 41.3 %