The proportion of dissolved substances in seawater is usually expressed in

A. parts per hundred.

B. parts per thousand.

C. parts per ten thousand.

D. parts per million.

What is an oxidation state?

How does the melting of glaciers affect the density of water at the earth's poles?

The addition of a catalyst to a chemical reaction will have what effect? A. Increase the energy required for the reaction to take place. B. Increase the time required for the reaction to take place. C.

The buildup of which substance causes muscle fatigue and soreness after exercising? lactic acid glucose carbon dioxide glycogen

Calculate the energy if 48.7 g of Al reacts in the following reaction. (Al = 26.98 g/mol) Fe2O3 (s) + 2 Al (s) →Al2O3 (s) + 2Fe (s) ∆Hrxn = - 852 kJ.

Write the net ionic equation for the reaction between agno3 (aq) and na2so4 (aq). be sure to include states of matter in your answer.

Witch compound has an element ratio of 2:1

Consider the total ionic equation below. 2 upper N upper H subscript 4 superscript plus, plus 2 upper O upper H superscript minus, plus 2 upper H superscript plus, plus upper S upper O subscript 4 superscript 2 minus right arrow 2 upper N upper H

Which of the following is true regarding phase changes? A. Condensation is the reverse of evaporation. B. Melting is the reverse of deposition. C. Freezing is the same as sublimation. D. Sublimation is the same as boiling.

Which of the following adaptations to life on land is found in both insects and modern reptiles? A. metamorphosis from a larval form B. body surfaces that resist evaporation C. tracheae to distribute oxygen D. ability to fly E.