In a lava lamp, a waxy substance rises and falls repeatedly. What causes the waxy substance to rise?

A) The waxy substance is cold.
B) The waxy substance is warm.
C) The waxy substance is less dense than the surrounding liquid.
D) The waxy substance is more dense than the surrounding liquid. Convection is occurring.

Which is true of chemicals? a. things containing chemicals always cost a lot of money. b. chemicals are never dangerous. c. chemicals are in many substances in a home. d. chemicals are rarely found on earth.

Calcium hydride (cah2) reacts with water to form hydrogen gas: cah2(s) + 2h2o(l) → ca(oh)2(aq) + 2h2(g) how many grams of cah2 are needed to generate 45.0 l of h2 gas at a pressure of 0.995 atm and a temperature of 32 °c?

Select the correct answer. which statement is true about a polarized object? o a. it gains electrons and becomes negatively charged. ob. it gains protons and becomes positively charged. oc. the number of positive and negative charges can be the same. od. it has to be a metal. o e. there is no change in the distribution of the charge in the object. reset next what