A puddle of water on the porch disappears after a few days. Which statement justifies this phenomenon?

Why are hydrogen bonds important for the properties of water?

A block of aluminum occupies a volume of 15.0 mL abd weighs 40.5 g. What is its density?

A 1.18 L sample of gas at 759 mm Hg pressure is expanded until its volume is 2.06 L. What will be the pressure in the expanded gas sample (at constant temperature) ?

What do all atoms in one element have in common? What can be said about the number of electrons atoms of one element can have?

Hydrocarbons are separated from each other by a process called cracking distillation. a. True b. False

What changes do you shown in the model

Select all the correct answers. What are the products of the acid-base reaction between HClO3 and LiOH? LiClO4 H2O LiH LiClO3 HClO4

Under what conditions will light bend? a) Never b) When it slows down while going through space c) When it speeds up while going through space d) When it passes from one medium to another

Cells can manipulate the free energy of reactions by: (Select all that apply) Changing the concentrations of products and reactants Changing the concentration of the enzyme involved in the reaction Using enzymes A.

NH3 is an example of A. an element. B. an atom. C. a mixture. D. a compound.