Chemistry homework

Question

A  container holds a mixture of two gases at  The partial pressures of gas A and gas B, respectively, are  and  If  of a third gas is added with no change in volume or temperature, what will the total pressure become?

Answer 1

According to Daltons Law, partial pressures are additive...gases (at least ideal gases) don't react with each other, so each one behaves like it is the only gas present when it occupies a volume. They ignore each other, you could say. So you should be able to just add the new pressure to the given pressures of the existing gases (provided they are in the same units) to get the new total pressure. (this won't work if volume or temperature change, but the problem says they don't, so Dalton's Law applies)