What is a way to find what 7 is what percent of 20 and i can't use a percent bar model?

(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 ?

What is the simplified form of (3.25x10^3)(7.8x10^6) written in scientific notation?

Polygon abcde is reflected to produce polygon a′b′c′d′e′. what is the equation for the line of reflection?