Which element is present in all organic compounds?

a. carbon

b. hydrogen

c. nitrogen

d. oxygen?

When does the northern hemisphere receive the fewest direct rays from the sun During the fall equinox During the winter solstice During the spring equinox During the summer solstice

Which of the following molecules is predicted to have the smallest molecular dipole moment? HI HCl H2 HBr

A gaseous sample of pure methane, CH4, is found to occupy a volume of 20.0 L at 25℃ and 1 atm pressure. What volume of O2, at the same temperature and pressure, should be just sufficient to permit complete combustion of the methane? 10.0 L 20.0 L 30.

You are a meteorologist measuring the changing air pressure due to an approaching weather front. What instrument would you use to measure atmospheric pressure?

According to kinetic molecular theory, which of the following statements is true about the behavior of gases? a. The particles of a gas are in constant, random motion. b.

What is the lowest energy level that contains d orbitals? O A. 4 O B. 1 O c. 3 O D. 2

What is the nature of the Ca-Cl bond in a molecule of calcium chloride (CaCl2) if the electronegativity value of calcium is 1.0 and that of chlorine is 3.167 O A nonpolar covalent B. moderately polar covalent C.

Which statement is true about oxidation and reduction in an electrochemical cell? (1) Both occur at the anode. (2) Both occur at the cathode. (3) Oxidation occurs at the anode and reduction occurs at the cathode.

For a solar eclipse to occur,

How many times does the citric acid cycle occur for each molecule of glucose?