Which of the following is an example of an irreversible physical change? A. Melting a piece of lead B. Boiling water C. Sharpening a pencil D. Dissolving sugar into water

What are the four main states of matter

Why does silicon in silicon dioxide bond with 4 oxygen atoms and not 2? But carbon in carbon dioxide bonds with 2 oxygen atoms but not 4?

Alchemists were medieval scholars and philosophers who were the forerunners of modern-day chemists. many tried repeatedly to transform lead (atomic number 82) into gold (atomic number 79). explain why they never did succeed.

In which sample of water do the water particles have more energy: 5 grams of ice cubes at - 10 degrees Celsius or 5 grams of liquid water at 20 degrees Celsius? How do you know

Which noble gas is closest to magnesium

A 25 N and 5 N force pull to the right. Friction is 10 N. If the object is 5 kg, find the net force and acceleration.

What properties of matter are intensive independent of their size

What is the density of an object having a mass of 8.0g and a volume of 25cm3

What is a Cilla? (In drawing)

Which term names the group of organisms able to interbreed and produce fertile offspring?