<span>because it is a pattern; airgo cycle</span>
(P1V1/T1)=(P2V2/T2)
I just took the test and this should be correct
Answer:

Explanation:
The pressure, the volume and the temperature of an ideal gas are related to each other by the equation of state:

where
p is the pressure of the gas
V is the volume of the gas
n is the number of moles
R is the gas constant
T is the absolute temperature
For the gas in this problem:
n = 2.00 mol is the number of moles
V = 17.4 L is the gas volume
p = 3.00 atm is the gas pressure
is the absolute temperature
Solving for R, we find the gas constant:

Based on the chemical equation, 4 moles of lithium reacts with 1 mole of oxygen to produce 2 moles of lithium oxide.
First of all you need to find 1 mole of Lithium by diving 1.68 mol by 4 and the answer should be 0.42 mol. To calculate the no. of moles of lithium oxide, you've to multiply 0.42 mol by 2. Hence the answer, 0.84 mol.
Different explanations that lead to the same result
-You need to substract the number of protons from the mass number.
-Mass number - atomic number= number of protons
-Following this equation:
CARBON
atomic number= 6
mass number= 12
mass number= protons + neutrons
12= 6 + x
x= 12-6
x= 6