An element X belongs to 4th period and 17th group. Write the formula of the compound formed when it reacts with Y (atomic no.-13, mass no. 27.)

In each case, decide if the change is a "chemical change" or a "physical change". a) A cup of household bleach changes the color of your favorite T-shirt from purple to pink. b) Water vapor in your exhaled breath condenses in the air on a cold day.

What is the hydroxide ion concentration in a solution of NH3 with a pOH of 4.65? * 10n M

The number of moles of solute dissolved per liter of solution; also known as molar concentration.

Isotopes of the same element must have the same number of - a protons + neutrons. b neutrons. c electrons. d protons.

When 40.5 g of Al and 212.7 g of Cl2 combine in the reaction: 2 Al (s) + 3 Cl2 (g) - -> 2 AlCl3 (s) b) How many moles of AlCl3 are formed?

What is it called when copper can be stretched into s thin wire?

What river basin provide river water to charolette and gastoia?

8. Calculate the molar mass of an alkane with the mole- cular formula C H18.

What is DNA? What information does it carry? Where is DNA located?

5. Differences in which property allow the separation of a sample of sand and seawater by filtration? A) concentration of ions B) volume of sample C) mass of sample D) particle size