The original amount of radioactive substance is 10 grams. After several years, 2.5 gtams of the substance is remaining. How many half-lives havr passed since the mass of the subtance was 10 grams?

Which of the following has zero acceleration? A. A satellite orbiting at a constant speed. B. A car making a turn at a constant speed. C. A person running 100 m straight across a field at a constant speed. D.

A solution that has a large amount of dissolved solute is called

The addition of a catalyst in a chemical reaction (A) increases the concentration of products at equilibrium. (B) increases the fraction of reactant molecules with a given kinetic energy.

A water sample from a hot thermal vent contained a single-celled organism that had a cell wall but lacked a nucleus. What is its most likely classification?

Why does refrigerated food stay fresh longer than food that is kept at room temperature

What is the golden rule of lighting safety?

Select the correct answer. A man pours some hot coffee into a small cup from a large jug that contains enough coffee for several cups. Which statement correctly compares the coffee in the cup and in the jug? A.

Is sponge cake a heterogeneous mixture

Describe three skills people use to conduct scientific investigations

The surface temperature on Venus may approach 739 K. What is this temperature in degrees Celsius?