Which of the following represents a chemical change?

A. Bending a wire

B. Freezing of water

C. Fireworks exploding

D. Melting of a wax candle

:D

2. A solution of potassium cyanide, KCN, is made by dissolving 3.2 g of KCN in water. When this solution reacts with excess hydrochloric acid, HCl, it produces 0.30 g of poisonous hydrogen cyanide gas, HCN.

The longer the reaction time is, the the reaction rate is. Reaction time is to reaction rate.

onsider the reversible dissolution of lead (II) chloride. P b C l 2 (s) - ⇀ ↽ - P b 2 + (a q) + 2 C l - (a q) PbClX2 (s) ↽--⇀PbX2 + (aq) + 2ClX - (aq) Suppose you add 0.2393 g of P b C l 2 (s) PbClX2 (s) to 50.0 mL of water.

How would a solution that is labeled 5.0 molar be similar to one labeled 5.0 molal?

How are the helium atoms in a glass model different from real atoms

How many electrons are contained in an Au3 + ion? (1) 76 (3) 82 (2) 79 (4) 197

Match the element with its number of valence electrons. Column A 1. Boron : Boron 2. Carbon : Carbon 3. Fluorine : Fluorine 4. Sodium : Sodium Column B a. 4 b. 1 c. 3 d. 7

The number of energy levels to which an electron can jump depends on the

The example of the ancient fish called a coelacanth was used to show us that science is constantly seeking new A) evidence B) ideas C) creatures D) Scientists

What factors allowed the koala population to grow beyond what their habitat could sustain?