Answer:
The pH of a solution is a measure of the molar concentration of hydrogen ions in the solution and as such is a measure of the acidity or basicity of the solution.
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
Based on the given conditions, the gravitational force acted on the body is greater than the force upward by a quantity equal to 500 N. Therefore, the net force will cancel out and will remain an amount of 500N downward relative to the gravitational force exerted by the object.
Answer:
Electrons will flow from left to right through the wire.
Pb^2+ ions will be reduccd to Pb metal.
The concentration of Sn2+ ions in the left compartment will increase.
Explanation:
Looking at the relative electrode potentials of the two metals
Sn= -0.14
Pb=-0.13
Tin is expected to function as the anode (left hand half cell) and lead as the anode (right hand half cell) tin oxidizes to sn^2+ hence its concentration increases on the left compartment while lead is reduced to ordinary lead metal on the right hand half cell . since oxidation occurs on the left hand side, electrons flow from left to right.