Answer:
A. The balloons will increase to twice their original volume.
Explanation:
Boyle's law states that the pressure exerted on a gas is inversely proportional to the volume occupied by the gas at constant temperature. That is:
P ∝ 1/V
P = k/V
PV = k (constant)
P = pressure, V = volume.

Let the initial pressure of the balloon be P, i.e.
, initial volume be V, i.e.
. The pressure is then halved, i.e.

Therefore the balloon volume will increase to twice their original volume.
Answer: the heat content of a system at constant pressure.
Explanation:
Enthalpy is defined as the heat content of a system at constant pressure.
It is the heat absorbed or released during a reaction at constant pressure,denoted as ΔH.
Correct Answer: compound because the atoms of the elements are combined in a fixed proportion.
Alright, so that means we have 0.68 mol of the compound
For each 1 mol of the compound, we have 4*1 oxygens (because there are four oxygens in the formula)
Therefore for each 0.68 mol of the compound, we have 4*0.68 moles of oxygen!
White gold is made out of yellow gold mixed with other metals, which are added to make the alloy harder and whiter.
Even when mixed with whiter metals, white gold still retains a yellowish hue.
The quality characteristic most often used to evaluate white gold is its karat.