Chemistry questions

In the periodic table of elements,, how are they arranged?

"So that elements with similar properties are in the same group."

What did Dalton theorize?

Compounds are composed of ratios of elements

Is smog heterogeneous or homogeneous mixture?

Heterogeneous because smog is a suspension so all suspensions are heterogenous.

Are homogeneous mixtures always pure substances? Explain.

Not always because a pure substance cannot be a mixture and homogeneous is a mixture.

What can scientists do when atom and molecules are so small?

Observe only indirect.

Why do you think breathing smog can be harmful?

You can start coughing heavily or headaches.

What temp. do pure substances boil at?

constant, known tempatures

What do you call a sample of matter that has more than one set of properties?

mixture

Water molecule?

one oxygen atom and two hydrogen atoms

What is an example of a material that looks homogeneous but is heterogeneous?

Colloid

What kind of mixture is alloy? What are two different examples of alloy? Why are alloys sometimes more useful than pure substance?

1. Metal mixture 2. Brass and stainless steal 3. Because both have combined two different metals that they were made out of.

What makes 24 karat gold? 22- karat gold? 14-karat gold? 12- karat gold?

100% gold. 92% gold 8% other metal 48% gold 42% other metal 50% gold 50% other metals

How are compound different from mixtures?

A compound is a pure substance. The compound is made of two or more elements. The mixture is made by mixing two or more elements The mixture is not.

How can chemical change help you tell the difference between an element and compound?

An element is a pure substance and it cannot be reversed once it has something done to it while chemical change. ( Cannot be broken or separated) A compound has two or more combined elements that are combined in a chemical change.

What are the symbols of oxygen atom, carbon atom, hydrogen atom?

Atom= Red big dot Carbon= Same size as oxygen but black dot Hydrogen= Small blue dot

How are atom and molecule different? Same?

The atom is a tiny particle that makes up matter. A molecule is a small particle made up of two or more atoms combined. The atom is in everything in the world. Same: both are tiny. Are individual unts of a pure substance. Both consist at least one atom.

How is mixture different from a pure substance?

The mixture has a combination of two or more types of matter. Pure substances have only one type of matter. Pure substance is an element. Mixture is too. A pure substance cannot be separated, but a mixture can.

How are suspension, solution, and emlusion same?

All of them are some kind of mixture and sometimes you can see things in it.

How do element and atom differ? Same?

Element is a pure substance made of only one type of atom. The atom is a tiny particle that makes up matter. Have different numbers of atoms. Same: only have one atom included in it. They both have protons and neutrons.

Why do pure substances always have the same properties?

Every pure substance has its own type of particle which is different from other particles that make up up all other pure substances.

The pure substance carbon is what?

Example of homogeneous mixture?