Answer:
Explanation:
Vaporization Equation => Q = m·ΔHv
m = 0.5Kg water = 500g water
ΔHv = Heat of vaporization = 540 calories/gram
∴Q = 500g x 540cal/g = 270,000 calories x 4.184 joules/cal = 1,129,680 joules = 1130 Kilojoules (3 sig. figs.)
If they have 3 chemistry classes with 24 students, than there are 72 students in total. Each student requires 4 test tubes. 72 * 4 = 288 test tubes. Our answer is C.) 288 test tubes
More dissolved oxygen is present in water with a lower temperature compared to water with a higher temperature. The reason for this inverse relationship between dissolved oxygen and temperature is that the solubility of a gas in a liquid is an equilibrium phenomenon.
I don't have a calculator with me right now, but that mass would be 1200 grams. Divide the given amount of grams by the molar mass of NH3, which is 17.031g/mol. (Nitrogen + 3(hydrogen)). Again, sorry I didn't have a calculator. But all you would need to do is divide 1200 by 17.031. If you need to use sig figs, your answer should have 2 because the 1.2 x 10^3 limits your amount of sig figs.