Please help me with this homework

(a) calculate the molarity of a solution that contains 0.0345 mol nh4cl in 400 ml of solution. (b) how many moles of hno3 are present in 35.0 ml of a 2.20 m solution of nitric acid? (c) how many milliliters of 1.50 m koh solution are needed to supply 0.125 mil of koh ?

Asphere has a diameter of 10 in. what is the volume of the sphere?

Point r divides in the ratio 1 : 3. if the x-coordinate of r is -1 and the x-coordinate of p is -3, what is the x-coordinate of q? a. b. 3 c. 5 d. 6 e. -9