What is the mass of a sample of NH3 containing 6.3 x 1024 molecules of NH3? O 157 grams
O 178 grams
O 182 grams
198 grams

Sylvanite is a mineral that contains 28.0% gold by mass. how much sylvanite would you need to dig up to obtain 77.0 g of gold? explain how you got your answer and the steps you took. you

Calculate the ratio of h+ ions to oh– ions at a ph = 7. find the concentration of h+ ions to oh– ions listed in table b of your student guide. then divide the h+ concentration by the oh– concentration. record this calculated ratio in table a of your student guide. compare your approximated and calculated ratios of h+ ions to oh– ions at a ph = 7. are they the same? why or why not? record your comparison in table a. what is the concentration of h+ ions at a ph = 7? mol/l what is the concentration of oh– ions at a ph = 7? mol/l what is the ratio of h+ ions to oh– ions at a ph = 7? : 1

Scientific evidence tells us that the cause of earths four season is the tilt of earth as it revolves around the sun. the student is instructed to illustrate this information in a science notebook. how will the student illiterate winter in the northern hemisphere?