10. How do substances change after a chemical reaction? cal

A They lose mass.

B Their atoms are rearranged.

C Their atoms lose electrons.

D They change phase.

Why do very few trees exist in a grassland ecosystem? A. not enough heat B. not enough topsoil C. not enough sunlight D. not enough precipitation

What two things determine whether a molecule is polar? Check all that apply. A. The size of the atoms that make up the molecule B. Whether or not there are bonds of two atoms of unequal electronegativity C. Whether there is a double bond D.

Determine the binding energy per nucleon of an Mg-24 nucleus. The Mg-24 nucleus has a mass of 23.985045. A proton has a mass of 1.00728 amu, a neutron has a mass of 1.008665 amu, and 1 amu is equivalent to 931.5 MeV of energy.

When an organism dies, what happens to the nutrients that have been transferred to it? A. The nutrients are lost. B. The nutrients are recycled back to the soil. C. The nutrients are multiplied. D. The nutrients cause the organism to rot and decay.

A mixture of 100 g of k2cr207 and 200 g of water is stirred at 60 °c until no more of the salt dissolves. the resulting solution is poured off, leaving the undissolved solid behind. the solution is now cooled to 20°c.

Trevor watches as a freight train passes. He counts eight identical black railroad cars, then a red car, followed by several more black cars.

How long does a hydrogen bond last in water

If the body temperature of a person is recorded as 37°c, what is the person's body temperature in k? round your answer to the nearest whole number.

Pf3cl2 is a nonpolar molecule. based on this information, determine the f-p-f bond angle, the cl-p-cl bond angle, and the f-p-cl bond angle. enter the number of degrees of the f-p-f, cl-p-cl, and f-p-cl bond angles, separated by commas (e. g.

What is the empirical formula of a substance that contains 2.64g of C, 0.444g H and 3.52g of O