What characterizes a chemical change?

How many helium atoms are there in a helium blimp containing 535 kg of helium?

Identify each energy exchange as primarily heat or work and determine whether the sign of ΔE is positive or negative for the system. a. A rolling billiard ball collides with another billiard ball.

When two or more covalently bonded atoms combine chemically, we refer to the physical result as?

How many neutrons are in a neutral atom of aluminum

Calculate the volume (in ml) of 0.170 m naoh that must be added to 389 ml of 0.0543 m 3 - (n-morpholino) propanesulfonic acid (mops) to give the solution a ph of 7.55. the pka of mops = 7.18.

Suppose you find a rock that contains some potassium-40 (half-life of 1.3 billion years). you measure the amount and determine that there are 5 grams of potassium-40 in the rock.

What are some positive and negative effects of the production of maple syrup on society and the environment?

Describe and give an example of parasitism.

Why is a dilute solution of oleic acid used instead of pure oleic acid?

The vapor pressure of benzene (C6H6) is 73.0 mm Hg at 25 °C. What is the vapor pressure of a solution consisting of 179 g of benzene and 0.217 mol of a nonvolatile nonelectrolyte?