Which two elements make up the greatest percentages by mass in Earth’s crust? (1) oxygen and potassium
(2) oxygen and silicon
(3) aluminum and potassium
(4) aluminum and silicon

Match the name of the following compound:   mgso4  · h2omagnesium sulfate monohydratemagnesium (ii) sulfate monohydratemagnesium (ii) sulfate hydratemagnesium sulfate hydrate

Astudent pours 10.0 g of salt into a container of water and observes the amount of time it takes for the salt to dissolve. she then repeats the process using the same amounts of salt and water but this time she slowly stirs the mixture while it is dissolving. the student performs the experiment one more time but this time she stirs the mixture rapidly. the dependent variable in this experiment is: time for salt to dissolve speed of stirring amount of water mass of salt

Which elements are found in glucose, the product of photosynthesis? a. carbon, hydrogen, and oxygen b. carbon and hydrogen c. carbon, nitrogen, and oxygen d. hydrogen, nitrogen, and carbon