Explain why elements and compounds are pure substances

How are we able to see planets in the night sky?

What name is given to the process a solid becomes a liquid? a liquid becomes a gas; I have had a think about it is it melting when a solid becomes a liquid a liquid becomes a solid?

Rewrite using a single exponent 5 (4) • 5 (3)

What metric unit is used for measuring an eyelash?

Which are true statements about reactions? Check all that apply. A. In a chemical reaction, the nucleus is breaking apart. B. In a chemical reaction, bonds between atoms break apart. C. In a chemical reaction, electrons are given, taken, or shared.

Given the balanced equation representing a reaction: C3H8 (g) + 5O2 (g) = = >3CO2 (g) + 4H2O (g) What is the total number of moles of O2 (g) required for the complete combustion of 1.5 moles of C3H8 (g) ? (1) 0.30 mol (3) 4.5 mol (2) 1.5 mol (4) 7.

What increases in equal steps of one from left to right in the Periodic Table for the elements lithium to neon?

The organisms living together in a community are interdependent upon one another. Look at the food web below. In which of the following ways is a puffin dependent upon salmon? A. Puffins have a commensalistic relationship with salmon. B.

2) Which of the following is a true statement? A: All the atoms of an element must be identical. B: Compounds may be separated by physical means. C: Mixtures may not be separated. D: Homogeneous is one type of compound.

How to tell the difference between ionic and covalent bonding?