Astudent reduces the temperature of a 300 cm3 balloon from 60°c to 30°
c. what will the new volume of the balloon be? (remember to be careful with the units.)

We can use the ideal gas equation which is expressed as PV = nRT. At a constant pressure and number of moles of the gas the ratio T/V is equal to some constant. At another set of condition of temperature, the constant is still the same. Calculations are as follows:

T1 / V1 = T2 / V2

V2 = T2 x V1 / T1

V2 = 303.15  x 300 / 333.15

V2 = 272.99 cm³

answer; /// i do believe that the correct answer is (a) boiling

the atomic mass is the bottom number on the element.

-steel jelly