Which species represents a chemical compound?

(1) N2 (3) Na

(2) NH4 + (4) NaHCO3

How many neutrons are in a typical silicon atom? A. 15 B. 14 C. 28 D. 42

Examine the following false statement. Acids that have a low pH are strong acids while acids that have a high pH are weak acids.

A school board is concerned that student test scores are being affected by the fact that students do not get enough sleep at night. Which of the following is a testable hypothesis to use for finding whether or not this is true? A.

Covalent bonds usually occur between atoms that have and. A. High molecular weights; large atomic radii B. Low ionization energies; low electron affinities C. Low molecular weights; small atomic radii D.

How much heat is absorbed by 20g granite boulder as energy from the sun causes its temperature to change from 10 degrees Celsius to 29 degrees Celsius (specific heat capacity of granite is 0.1 cal/g degrees Celsius

Where do you think information is coded in a DNA molecule?

The mole fraction of carbon dioxide in a gas mixture is. 200 there are also. 251 g of nitrogen and. 322 g of oxygen in this gas mixture what is the mass of arbon dioxide in this mixture

How do you do empirical formula

Classify the same processes as exothermic or endothermic. Evaporation of alcohol from skin: liquid C3H30 + 5.

Is this molecule polar? NaS