Which of the following is an example of a chemical change?

a. water evaporating from a puddle on a hot day

b. burning a piece of toast

c. cracking open an egg and removing the yolk

d. steam condensing on the bathroom mirror

What is the difence between high pressure and low pressure?

The reaction 2a + b - - > c + d has an activation energy of 80.0 kj/mol. at 320°c, the rate constant k = 1.80 x 10-2 l mol-1 s-1. what would be the value of k at 450°c?

Whats the effect to ocean plates move apart from eachother

Which elements are likely to gain electrons

An acetylide anion is more stable than either a vinylic or alkyl anion due to Group of answer choices the greater stability of an sp hybrid orbital. the stabilization of the negative charge in orbitals with higher s character.

The characteristic flame test colors of metal ions are due to atomic emission spectra. Duscuss the relationship between the absoption and emission of light and the factors responsible for flame test colors.

Should a bartender use ice and scoop directly from ice machine or use an ice holding device and scoop to make drinks and refill drinks from

What classification should this reaction have? 4Al + 3O2 → 2Al2O3

If you start with 100 grams of a radionuclide, how much will you have after two half-lives have passed?

Identify the spectator ions in the following complete ionic equation. 2k (aq) s2 - (aq) pb2 (aq) 2no-3 (aq) →pbs (s) 2k (aq) 2no-3 (aq) express your answers as ions separated by a comma.