What is the molarity of a solution in which 0.257 moles of HNO2 is dissolved in 490ml of water?

Suppose you wanted to make 100 grams of water. what is the molar mass of water (h2o)?

Question 3(multiple choice worth 4 points) (04.04 lc) what does it mean when an element is reduced? it empties a valance shell, reducing its atomic radius. it gains electrons, reducing its overall charge. it increases electronegativity, reducing its ability to bond. it loses electrons, reducing its electron number.

Can someone me out on this question for my national 5 chemistry homework