Why does a solution of naoh have to be standardized against a primary standard as supposed to just using the mass and volume to calculate the concentration

Over the last 90 years, scientists have added to the body of evidence supporting the big bang theory. what is the latest piece of evidence discovered in 2014?

How many grams of co(g) are there in 74.5 ml of the gas at 0.933 atm and 30o c?

6. using 3 – 4 sentences explain (in your own words) why water expands when it freezes? 7. using your knowledge of colligative properties explain whether sodium chloride or calcium chloride would be a more effective substance to melt the ice on a slick sidewalk. use 3 – 4 sentences in your explanation.