Which of these is an example of a physical change

baking a cake

toasting bread

grinding pepper

lighting up a grill

Which of the following alcohols is used antifreeze?

What is thermal expansion?

Describe the evidence for the existence of electrons?

What happens in an acid-base reaction according to the arrhenius definition?

In the development of atomic models, it was realized that the atom is mostly empty. Consider a model for the hydrogen atom where its nucleus is a sphere with a radius of roughly 10-15 m, and assume the electron orbits in a circle with a radius of

You are conducting an experiment on plant growth. You take a plant fresh from the soil that weighs 5 kilograms (kg). Then you dry the plant overnight and determine the dry weight to be 1 kg.

What is the ratio of Fe+3 ions to O2 - ions in a neutral compound? a. 1:2 b. 2:1 c. 2:3 d. 3:2

What is the specific heat capacity of a 17.5g sample of an unknown metal that releases 6700J of heat when it cools from 90 to 25 degrees C?

How can equilibrium of a closed system chemical reaction be disturbed? Select all that apply. Adding or removing products or reactants. Keeping the concentration of products and reactants the same. Keeping the temperature of the system constant.

Why does an exothermic reaction need activation energy?