Why are there only two elements in the first row of the periodic table?

Leslie is observing the air in a balloon. She wants to know if the air in the balloon is matter. What must be true of the air for it to be matter?

Nitrogen gas is being held in a 14.3 L tank at a temperature of 62°C. What will the volume be when the temperature drops to 24°C?

In which medium would light have the longest wavelength?

How do machines transfer and convert energy

Most of the volume of a gas is

The percentage of carbon dioxide in the atmosphere has increased in the last century and is a concern for the environment as it increases the greenhouse effect. Give one possible explanation for the increase of carbon dioxide in the atmosphere

Is KBr an acid or base

if you read the the liqud volume where the liqud touches the wall of the cylinder rather than at the meniscus

Design an experiment using a radioactive tracer to evaluate the amount of wear on steel auto engine cylinders using different types of lubricating oils. How should I do this? Any Ideas?

A non-metallic atom (at. no. 9) forms a molecule of the same, containing a single covalent bond. give reason