A substance that can be separated into two or more substances only by a chemical change is

What must be done to be certain that a chemical change has taken place? a. Check for the production of bubbles before and after the change. b. Demonstrate that a release of energy occurred after the change. c.

List five characteristics of a molecule that can be determined from a lewis structure

How are salts formed? By the covalent bonding of neutral atoms. By the covalent bonding of oppositely charged ions. By the ionic bonding of a cation and an anion. By intermolecular hydrogen bonding.

Which of the following is a covalent compound containing polar bonds? a. OCl2. b. AlCl3. c. CO2.

Chemical properties a. include changes of state of a substance b. include mass and color c. include changes that alter the identity of a substance d. can be observed without altering the identity of a substance

Using the periodic table, determine the number of neutrons in a carbon.

Sailin Steve likes to test the buoyancy of different objects. He threw a spherical object into a fluid that has a greater density than the object does. He also threw a square object into the fluid that has a greater density than the fluid.

The sun is directly overhead at the equator on what day of the year? A. Zenith B. Solstice C. Equinox D. Ecliptic Isn't it the Solstice?

In the SI system of units, the mole is one of seven base units. It is frequently used in chemical calculations. However, a mole of something is just a particular quantity of it.

A student used a DCP solution (standardized to 9.98x10-4M) to analyze a sample of extract from 2.50g of solid food. The titration required 22.49mL of DCP. 87.00% of all the ascorbic acid in the food was collected in the extract.