A 5.25% by mass aqueous solution of Nal can be prepared by dissolving A. 5.25g Nal in 94.75ml water B. 1.00g Nal in 100g water C. 5.25mol Nal in 1.00L solution D. 5.25 mol Nal in 1.00kg water. The answer is A, but I'm not sure how you would know. If you can explain why that would be awesome!!

Agas mixture with a total pressure of 745 mmhg contains each of the following gases at the indicated partial pressures: co2, 245 mmhg ; ar, 119 mmhg ; and o2, 163 mmhg . the mixture also contains helium gas. part a what is the partial pressure of the helium gas? phe p h e = nothing mmhg request answer part b what mass of helium gas is present in a 10.2-l sample of this mixture at 283 k ? m m = nothing g request answer

Which of the following is an example of physical change not a chemical change? a) a log gives off heat and light as it burns. b) a tree stores energy from the sun in its fruit. c) a penny lost in the grass slowly changes color. d) a water pipe freezes and cracks on a cold night.

What is the molecular weight of copper