Molar mass of N2 = 28
Moles of N2 = 25 / 28 = 0.89
So, moles of NH3 produce = 2 x 0.89 = 1.78
Note: H2 is in excess. so no need to care about it.
4 moles of hydrogen = 4 * 1.008 = 4.032 grams
1 mole of helium = 4.003 grams
Difference is 4.032 - 4.003
= 0.029 g
Answer:

Explanation:
Henry's law states that the solubility of a gas is directly proportional to its partial pressure. The equation may be written as:

Where
is Henry's law constant.
Our strategy will be to identify the Henry's law constant for oxygen given the initial conditions and then use it to find the solubility at different conditions.
Given initially:

Also, at sea level, we have an atmospheric pressure of:

Given mole fraction:

According to Dalton's law of partial pressures, the partial pressure of oxygen is equal to the product of its mole fraction and the total pressure:

Then the equation becomes:

Solve for
:

Now we're given that at an altitude of 12,000 ft, the atmospheric pressure is now:

Apply Henry's law using the constant we found:

<u>Answer:</u> The molarity of calcium hydroxide in the solution is 0.1 M
<u>Explanation:</u>
To calculate the concentration of base, we use the equation given by neutralization reaction:

where,
are the n-factor, molarity and volume of acid which is 
are the n-factor, molarity and volume of base which is 
We are given:

Putting values in above equation, we get:

Hence, the molarity of
in the solution is 0.1 M.
I’m pretty sure the correct answer is D.