The question is incomplete, here is a complete question.
An arctic weather balloon is filled with 27.8 L of helium gas inside a prep shed. The temperature inside the shed is 13 ⁰C. The balloon is then taken outside, where the temperature is -9 ⁰C. Calculate the new volume of the balloon. You may assume the pressure on the balloon stays constant at exactly 1 atm. Be sure your answer has the correct number of significant digits.
Answer : The new volume of the balloon is 25.7 L
Explanation :
Charles's Law : It is defined as the volume of the gas is directly proportional to the temperature of the gas at constant pressure and number of moles.

or,

where,
= initial volume of gas = 27.8 L
= final volume of gas = ?
= initial temperature of gas = 
= final temperature of gas = 
Now put all the given values in the above equation, we get:


Therefore, the new volume of the balloon is 25.7 L
The molecule that contains the fewest number of Hydrogen atoms would be B. Al(OH)3. It only has 3 Hydrogen atoms.
The weighted average of the nail in accordance with the given data is 11.176g.
<h3>How to calculate weighted average?</h3>
Weighted average is an arithmetic mean of values biased according to agreed weightings.
The weighted average of the nail in the image above can be calculated by multiplying the decimal abundance with the mass of the nail, then summed up as follows;
Weighted average = (decimal abundance × mass 1) + (decimal abundance × mass 2)
Weighted average = (0.12 × 3.3) + (0.88 × 12.25)
Weighted average = 0.396 + 10.78
Weighted average = 11.176g
Therefore, 11.176g is the weighted average of the nail
Learn more about weighted average at: brainly.com/question/28042295
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Hey there! The answer to your first question is SILICON, Nickle has 28 protons, silicon has 14, 14+14=28. Its the only element thats adds up. I dont know about the 2nd one myself.