Can someone help explain in the simplest fashion how to do these please??

1. How many liters of oxygen gas, at standard temperature and pressure, will react with 35.4 grams of calcium metal? Show all of the work used to solve this problem.
2 Ca + O2 -- 2 CaO

2. How many grams of water vapor (H2O) are in a 10.2 liter sample at 0.98 atmospheres and 26°C? Show all work used to solve this problem.

3. If 34.2 grams of lithium react with excess water, how many liters of hydrogen gas can be produced at 299 Kelvin and 1.21 atmospheres? Show all of the work used to solve this problem.

Question

Can someone help explain in the simplest fashion how to do these please??

1. How many liters of oxygen gas, at standard temperature and pressure, will react with 35.4 grams of calcium metal? Show all of the work used to solve this problem.
2 Ca + O2 --> 2 CaO

2. How many grams of water vapor (H2O) are in a 10.2 liter sample at 0.98 atmospheres and 26°C? Show all work used to solve this problem.

3. If 34.2 grams of lithium react with excess water, how many liters of hydrogen gas can be produced at 299 Kelvin and 1.21 atmospheres? Show all of the work used to solve this problem.

bloosweater · Answer

Equation for no. 3:
2 Li (s) + 2 H2O (l) yields 2 LiOH (aq) + H2 (g)

dtan5457 · Answer

Ok..first one. You are aware that under STP, volume=22.4 liters per mole?

How many moles are in calcium with 35.4 grams?

that would be given mass/formula mass

there are two moles of Ca, so the formula mass would be 80.

35.4/80= 0.4425 moles

two moles, so divide by 2

0.22125 x22.4=?

dtan5457 · Answer

the 2nd, one use the ideal gas law and convert celcius to kelvins.

ideal gas law is

pV=NRT

p=pressure
v=volume
n=number of moles
r=0.0821 (in this case since pressure is in atm and volume is in liters)
t=temperature in kelvins

dtan5457 · Answer

as for the third, one same thing, you use the ideal gas law

the only extra step is getting the amount of moles for hydrogen

bloosweater · Answer

Thank you so much :D

dtan5457 · Answer

yeah. go give them a try and tell me what you get

bloosweater · Answer

For the first question, I'm asking another friend as well and they keep telling me that all I need to do is substitute 34.5 into the equation and then balance further to end up with 0.0177L. Is this right..?

dtan5457 · Answer

no lol

dtan5457 · Answer

look at my first explanation again

bloosweater · Answer

For your explanation I got 4.956

bloosweater · Answer

Gonna go with your solutions because they haven't done chemistry in a few years, haha

dtan5457 · Answer

well for the 2nd one just plug everything in, give it a try

bloosweater · Answer

For the second one i got 0.407 = n, did I plug everything in right?

bloosweater · Answer

Also I'm having a hard time with no.3 still, any other tips? :L