Aballoon has a volume of 1.34 liters with 2.00 moles of helium gas. how many moles of helium gas must be added to get the volume to 7.00 liters.

The reaction: (ch3)3cbr + oh− → (ch3)3coh + br− in a certain solvent is first order with respect to oh−. in several experiments, the rate constant k was determined at different temperatures. a plot of ln(k) vs 1/t was constructed and the slope of the line was -1.10 x 104 k with a y-intercept of 33.5. what is the value for k at a temperature of 25°c?