One similarity and one difference between an element and a mixture of elements

An atom of 14 6 c carbon decays by gamma decay which atom is left after the decay

Determine the enthalpy for this reaction: 2naoh (s) + co2 (g) →na2co3 (s) + h2o (l) express your answer in kilojoules per mole to one decimal place.

Why do liquids flow? a. The particles do not move. b. The particles are tightly packed together. c. The particles are not in a fixed place. b. The particles vibrate.

12.65 Determine whether an aqueous solution of each of the following salts has a pH equal to, greater than, or less than 7. If pH 7 or pH 7, write a chemical equation to justify your answer.

If a bacterial culture produces 60.0 mL of methane gas at 700.0 mm Hg, what volume would be produced at 760.0 mmHg

A flask containing 155cm^3 of hydrogen was collected under a pressure of 22.5kPa. What pressure would have been required in order for the volume of the gas to have been 90.0 cm^3 at constant temperature?

Which change is most likely to occur when a molecule of H2 and a molecule of I2 collide with proper orientation and sufficient energy? 1. a chemical change, because a compound is formed 2. a chemical change, because an element is formed 3.

Which substance is a diatomic molecule? a. he b. o2 c. co2 d. h2o?

What is the difference between the electronegativity values of sodium and bromine?

Which of the following elements is the most stable element? argon, manganese, phosphorus, robidium