Which of these is an example of a physical change

baking a cake

toasting bread

grinding pepper

lighting up a grill

Which dienes will react with ethene in a diels-alder reaction?

Scientists Pam and Alejandro were discussing a liquid found in the science lab that was missing it's label. In classifying the unknown liquid, they first needed to determine if the liquid is a mixture or pure substance.

Which of the following is the correct Lewis structure for ammonia (NH3) ? Note: Hydrogen and nitrogen have one and five valence electrons respectively.

When the [H+] in a solution is 1.7 * 10-9 M, what is the pOH

What is the empirical formula of a compound containing 24.56% potassium, 34.81% manganese, and 40.50% oxygen?

Which of the following equilibria would be impacted by a change in pressure? Select the correct answer below: H2 (g) + I2 (g) →2HI (g) NO (g) + O3 (g) →NO2 (g) + O2 (g) 2SO3 (g) →2SO2 (g) + O2 (g) CO (g) + H2O (g) →CO2 (g) + H2

A common stain remover is sold in concentrated form as 3M sodium hypochlorite (NaOCl). You need to create 400 milliliters of a 0.5M solution of sodium hypochlorite to fill a spray bottle. What volume of 3M sodium hypochlorite is needed? 15.0 mL 66.

A chemical reaction that takes in heat is called: exothermic endothermic a phase change

Which of the following lines (of latitude or longitude) would represent by 180 longitude? South Pole Equator Prime meridian North Pole International date line

63Ni decays by a first-order process via the emission of a beta particle. The 63Ni isotope has a half-life of 100. years. How long will it take for 65% of the nickel to undergo decay?