Difference between h and h2 in two, two points​

If 1.63 times 10 negative 4 of helium dissolves in 100.0g of water, what is the concentration in parts per million

According to the tide table below what time of day will the highest tide occur?

Cucl2 + 2nano3 cu(no3)2 + 2nacl what is the percent yield of nacl if 31.0 g of cucl2 reacts with excess nano3 to produce 21.2 g of nacl? 49.7% 58.4% 63.6% 78.7%