A gas contained in a steel tank has a pressure of 1.5 atm at a temperature of 320 K. What will be the gas pressure when the temperature changes to 450 K?

The diagram above shows the structures of an animal cell. Which structure controls cell reproduction?

If the total mass of the products in a reaction is 90 grams what was the total mass of the reactants

Why does every element except hydrogen need at least one neutron in its nucleus?

If 50 mL of 0.2 M NaC2H3O2 and 10 mL of 1.0 M HC2H3O2 are diluted to a final volume of 100 mL, what is the pH of the buffer solution?

Which organism has a central brain? A fish B flatworm C sponge D hydra

Which statement regarding water is true? Energy must be given off in order to break down the crystal lattice of ice to a liquid. Hydrogen bonds are stronger than covalent bonds. Liquid water is less dense than solid water.

Which of the following elements has the fewest valence electrons?. a. beryllium. b. boron. c. carbon. d. lithium

How many molecules are in 4.50 moles of H2O? A. 450 molecules B. 6.02 x 1023 molecules C. 2.71 x 1024 molecules D. 3.00 molecules

A sample of pure calcium fluoride with a mass of 15.0 g contains 7.70 g of calcium. How much calcium is contained in 45.0 g of calcium fluoride

If the mass of a material is 111 grams and the volume of the material is 11 cm3, what would the density of the material be?