Molar mass Li2CO3 = 73.89 g/mol
Molar mass Li = 6.94g/mol Li = 6.94*2 = 13.88g
% LI = 13.88/73.89*100 = 18.78% perfectly correct.
Halogens. Ex. fluorine can be the gas,bromine can be the liquid, and iodine could a solid all under room conditions.
Answer : The correct option is, 
Explanation :
To calculate the pressure of gas we are using ideal gas equation as:

where,
P = pressure of gas = ?
V = volume of gas = 0.046 L
n = number of moles of gas = 3.4
R = gas constant = 8.314 L.kPa/mol.K
T = temperature of gas = 298 K
Now put all the given values in the above formula, we get:


Therefore, the pressure of gas is, 
Answer:
Methane(CH₄).
Explanation:
- Thomas Graham found that, at a constant temperature and pressure the rates of effusion of various gases are inversely proportional to the square root of their masses.
<em>∨ ∝ 1/√M.</em>
where, ∨ is the rate of diffusion of the gas.
M is the molar mass of the gas.
<em>∨₁/∨₂ = √(M₂/M₁)</em>
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- The molar mass of different choices:
Carbon dioxide: 44.01 g/mol.
Water vapor
: 18.0 g/mol.
Ammonia (NH₃): 17.0 g/mol.
Methane(CH₄): 16.0 g.mol.
<em>Since, methane has the lowest molar mass. So, it will diffuse faster within a system.</em>