Which sample is a pure substance?

a test tube of zinc oxide

a container of zinc and oxygen

a flask of pond water

a jar of soil

What are the 3 main classes of elements?

Which of the following is the hottest part of the sun?

A large flask is evacuated and weighed, filled with argon gas, andthen reweighed. WHen reweighed, the flask is found to have gained3.224 g. It is again evacuated and then filled with gas of unknownmolar mass.

True of false? Scientists estimate that one thimble of soil could hold more than 20,000 microorganisms.

Which element has six valence electrons in each of its atoms in the ground state?

159 l of hydrogen gas reacts with excess chlorine gas. what is the maximum amount of gas product that can be formed at stp

You and your friends are at the park on a sunny day, and you are playing on the slide. As you sold down, the hot slide burns your legs. Explian why this happened and why you didn't burn your hands when you climbed up the rope ladder

The physical properties of a compound are similar to those of its elements. true or false

How many grams of water can form if 113 g of acetylene is burned?

A cracker crushed in water will test positive with iodine but negative with benedict's solution. A cracker crushed in water has another chemical called amylase added to it.