1) Answer:
moles of oxygen (n) = 1.86 moles
Explanation:
according to Boyle's law the formula to solve this problem is:
PV=nRt
when P is the pressure which equal 1.25 atm
and V is the volume which equal 37.5 L
n is the number of moles which we need to calculate it
R is constant which equal 0.082
t is the temperature in kelvin
By substitution:
1.25*37.5 = n * 0.082 * 307
So n = 1.86 moles
2) Answer:
the volume of oxygen gas = 34 L
Explanation:
at standard temperature and pressure (STP) 1 mole of gas will equal = 22.4L
So when we have 1.5 moles of oxygen at standard temperature and pressure (STP) so we will estimate it like that
1.5 moles *22.4 L/ 1 mole = approximately 34 L
3) Answer:
The volume of H2 = 2.29 L
Explanation:
according to the Balanced equation we can see that the molar ratio between Zn and H2 1 : 1
so to know the number of moles of H2 we will get it for Zn first :
number of moles Zn = mass of Zn / molar mass Zn
= 5.98 / 65.39 =0.0914 moles
so number of moles H2 = 0.09 moles
by substitution in the following formula:
PV = nRT
0.978 * V = 0.09 * 0.082 * 298
so The volume of H2 = 2.29 L
4) Answer:
Volume of O2 = 1.4 L
Explanation:
first we have to balance the equation:
2Na2O2 +2CO2 → 2Na2CO3 + O2
2 mole CO2 give 1 mole of O2 so the molar ratio is 2:1
at STP 1 mole of gas will equal = 22.4 L
??? moles of CO2 = 2.8
n CO2 = 0.125 moles so n O2 = 0.125 /2 = 0.0625 moles
so when 1 mole of as = 22.4
0.0625 moles O2 = ???
Volume of O2 =0.0625 moles * 22.4 L/ 1 mole
= 1.4 L
5) Answer:
the initial quantity of sodium metal used = 17.2 gram
Explanation:
at STP 1 mole of gas will equal = 22.4 L
so moles of H2 equal ?? when 8.40 liters of H2 gas were produced
so moles of H2 = 8.4/22.4 =0.375 moles
and according to the balanced equation the molar ratio between H2 ans Na is 1 : 2
so number of moles for Na = 0.375 *2 = 0.75 moles
to get the initial quantity of sodium metal (mass Na) = number of moles * molar mass
mass Na = 0.75 moles * 23 gm/mole= 17.25
6) Answer:
False
Explanation:
because STP means standard temperature and pressure. and the Standard temperature must be 273 K and the standard pressure must be 1 atm but in the question the temperature is 298 K not 273 K so , It is not a standard temperature
7) Answer:
22.4 liters
Explanation:
1 mole of gas will equal = 22.4 L
because at the Standard temperature must be 273 K and the standard pressure must be 1 atm
so V = nRT/P
=1 mole * 0.082 * 273 K / 1 aTm
= 22.4 liters
