# molecules grams moles finish here start here 1.27 correct units

## Presentation on theme: "molecules grams moles finish here start here 1.27 correct units"— Presentation transcript:

molecules grams moles finish here start here 1.27 correct units
#16 Find the mass in grams of 4.52 x 10-3 moles of C20H42 Mult. by Molar Mass molecules grams moles finish here start here 282.0 g 1mole 4.52 x 10-3 moles 1 X = 1.27 grams correct units for answer here given

Fe(OH)2 molecules grams moles finish here start here 1.27
#17 Calculate the mass in grams of 2.5 moles of Iron (II) hydroxide Fe(OH)2 Mult. by Molar Mass molecules grams moles finish here start here 2.5 moles 1 g 1mole = 1.27 grams X correct units for answer here given

B 10.8 molecules grams moles start here finish here .0343
#18 Find the number of moles in 3.70 x 10-1 (.370) grams of boron divide by Molar Mass molecules grams moles start here finish here 1 mole B 10.8 g 3.70 x 10-1 grams 1 .0343 X = moles correct units for answer here given

N2O3 molecules grams moles finish here start here .99 correct units
#19 Calculate the number of moles in 75.0 g of dinitrogen trioxide N2O3 = 76.0g/mole divide by Molar Mass molecules grams moles finish here start here 75 g 1 1 mole 76.0 g = .99 moles X correct units for answer here given

20. What is the volume of these gases
at standard temperature and pressure? (STP) grams moles molecules start here mult. by 22.4 volume finish here for most gases: 22.4 Liters 1 mole a x 10-3 moles CO2 3.20 x 10-3mol 1 22.4 liters 1 mole x = .0717 liters b moles N2 82.9 liters N2 22.4 liters 1 mole = 3.7 mole N2 1 x

21. At STP (standard temp. and pressure), what
volume do these gases occupy? grams moles molecules start here mult. by 22.4 volume for most gases: 22.4 Liters 1 mole finish here a moles He 1.25 mol 1 22.4 liters 1 mole x = 28.0 liters He b moles C2H6 7.5 liters C2H6 22.4 liters 1 mole = .335 mole C2H6 1 x

80.2 x = 22. A gaseous compound composed of sulfur and
oxygen, which is linked to the formation of acid rain, has a density of 3.58 g/liter at STP. What is the molar mass of this gas? We are given the gas in units of g/liter and need to find the molar mass which is in units of g/mole. Therefore we need to use the relationship between liters and moles (22.4 liters/mole) to solve this: 80.2 3.58 g 1 liter ? g 1 mole 22.4 liters 1 mole x =

3.74 x = 23. What is the density of krypton gas at STP? 83.8 g Kr
Krypton has like all normal gases 22.4 liters/mole at STP. Therefore, knowing this and the molar mass of krypton (from the periodic table) we solve as follows? 3.74 83.8 g Kr 1 mole 1 mole 22.4 liters ? g 1liter x =

molecules grams moles 24. Describe how to convert between the
mass and the number of moles of a substance divide. by Molar Mass molecules grams moles multiply by Molar Mass To go from grams to moles you need to divide by the molar mass To go from moles to grams you need to multiply by the molar mass

25. What is the volume of one mole of any gas
at STP? 22.4 Liters 1 mole

26. How many grams are in 5.66 moles of CaCO3?
5.66 moles x g = g CaCO3 mole

C2H6O 27. Find the number of moles in 508 g of ethanol (C2H6O)?
= 46.0g/mole 508 grams x mole = moles g

28. Calculate the volume, in liters, of 1.50 mol of Cl2 at STP.
1.5 moles x liters = moles mole

29. The density of an elemental gas is
g/liter at STP. What is the molar mass of the element? g x liters = g 1liter mole mole

30. The densities of gases A,B,and C are 1.25
2.86 and respectively. Calculate the molar mass of each substance. Identify each substance as ammonia, sulfur dioxide, chlorine, nitrogen, or methane. NH3 = 17.0g/mole SO2 = 64.1g/mole 1.25 g x 22.4 liter = 1 liter mole 28g mole Cl2 = 71.0g/mole N2 = 28.0g/mole CH4 = 16.0g/mole

30. The densities of gases A,B,and C are 1.25
2.86 and respectively. Calculate the molar mass of each substance. Identify each substance as ammonia, sulfur dioxide, chlorine, nitrogen, or methane. NH3 = 17.0g/mole SO2 = 64.1g/mole 2.86 g x 22.4 liter = 1 liter mole Cl2 = 71.0g/mole N2 = 28.0g/mole 64.1g mole CH4 = 16.0g/mole

30. The densities of gases A,B,and C are 1.25
2.86 and respectively. Calculate the molar mass of each substance. Identify each substance as ammonia, sulfur dioxide, chlorine, nitrogen, or methane. NH3 = 17.0g/mole SO2 = 64.1g/mole g x 22.4 liter = 1 liter mole Cl2 = 71.0g/mole N2 = 28.0g/mole 16.0g mole CH4 = 16.0g/mole

They would have the same number of molecules because the rule states
31. Three balloons filled with three different gaseous compounds each have a volume of 22.4 L at STP. Would these balloons have the same mass or contain the same number of molecules? Explain They would have the same number of molecules because the rule states that equal volumes of gases contain equal numbers of molecules. The masses are probably different depending on the molar mass of each gas.

Download ppt "molecules grams moles finish here start here 1.27 correct units"

Similar presentations