Please help me do this Qustion

If 10.0 ml of the solution on the right are withdrawn from the 100 ml beaker and diluted again in a similar manner, what is the new concentration? m nacl

Calcium hydride (cah2) reacts with water to form hydrogen gas: cah2(s) + 2h2o(l) → ca(oh)2(aq) + 2h2(g) how many grams of cah2 are needed to generate 45.0 l of h2 gas at a pressure of 0.995 atm and a temperature of 32 °c?

The wave shown on the electromagnetic spectrum disturb the medium it passes through a)different frequency. b)the same frequency .