In a chemical reaction, the difference between the potential energy of the products and the potential energy of the reactants is equal to the

(1) activation energy

(2) entropy of the system

(3) heat of fusion

(4) heat of reaction

Explain the structure and function of DNA. What important roles does the phosphate-sugar backbone, nitrogen bases, complementary strands, and hydrogen bonds play in the structure of DNA?

Which mass law (s) is/are demonstrated by the observation that a sample of potassium chloride from chile contains the same percent by mass of potassium as one from poland? a. law of conservation of mass b. law of definite composition c.

Purification of water by natural plants and wetlands

Two students design an experiment to see if pushing or pulling a box across the floor is more effective. The first student pushes the box across the floor a distance of 20 feet and the second student times how long it takes.

How many grams of NaOH are dissolved in 3.0 liters of a 2.0 molar solution? (The molar mass of NaOH = 40.00 g/mol) O 80 grams O 240 grams O 120 grams O 40 grams

Based on the kinetic molecular theory, which of the following statements is correct about the particles in a sample of gas? They have negligible kinetic energy. There is negligible force of attraction between them.

The greenish color of plant cells comes from a. the cell membrane b. chloroplasts c. ink

Describe what might happen to the water cycle if less solar energy reaches Earth and how Earths climate would be affected.

In addition to canyons, what other kinds of geologic formations might separate similar organisms

Iron has a density of 7.86 g/cm3. Calculate the volume (in dL) of a piece of iron having a mass of 4.79 kg.