How are rubies, emeralds, and sapphires formed?

What happed on monday march 10 2010

Caffeine is a: a. weak acid, with a pKa of ~8.0 b. weak acid, with a pKa of ~0.5 c. weak base, with a pKa of ~8.0 d. weak base, with a pKa of ~0.5

A student tested a sample of carbon (C) by combining it with water. There was no reaction between the carbon and water. The student concluded that carbon must be a group 18 element, since it was unreactive.

A waterfall is an example of:

Thallium consists of 29.5%Th-203 and 70.5%Th-205. What is the relative atomic mass of thallium?

How many liters of air are in a room that measures 10.0 ft * 11.0 ft and has an 8.00 ft ceiling? 1 in. = 2.54 cm (exactly); 1 L = 103 cm3

Which of these represents a chemical change? A) two compounds combining to form a mixture B) a mixture being separated into two elements C) a compound being separated into two elements D) an element changing state from solid to liquid

What properties would have caused early researchers to name hydrogen "inflammable air"

Enter the symbol of a sodium ion, Na+, followed by the formula of a sulfate ion, SO42-

When making a molar liquid solution from a dry chemical stock, you must know the molecular weight of the compound. (A) True (B) False