1) Which of the following is the best example of a physical change?

A) Sugar Dissolving in tea

B) Firefly Glowing

2) In the combustion of ethane, what is/are the reactants?

C2H6 + O2 = => CO2 + H2O

A) C2H6 and O2

B) CO2 and C2H6

Commercial grade fuming nitric acid contains about 90.0% HNO3 by mass with a density of 1.50 g/mL, calculate the molarity of the HNO3 solution.

Chemical bonds are likely to form when A. two atoms have the same number of electrons. B. an atom's outer energy level doesn't have the maximum number of electrons. C. an atom's nucleus has the same number of protons as neutrons. D.

Which moon phase comes after a first quarter moon? (Show and label it)

Criteria for evaluating alternative solutions includes all of the following except: a. Appropriateness b. Prediction c. Adequacy d. Efficiency

Explain how the temperature of a substance is related to the kinetic energy of its molecules. Answer: Every substance is composed of molecules that have kinetic energy.

What is the percent by mass of nahco3 in a solution containing 10 g of nahco3 dissolved in 400 ml of h2o?

Consider the reaction: 2clf3 (g) + 2nh3 (g) → n2 (g) + 6hf (g) + cl2 (g) when calculating the δh°rxn, why is the δhf° for n2 not important?

12.5 g of copper are reacted with an excess of chlorine gas, and 25.4 g of copper (II) chloride are obtained. Calculate the theoretical yield and the percent yield.

Section 20.1 the meaning of oxidation and reduction answer key

How did fossil fuels come about? inorganic materials beneath the sea the remains of plants and animals millions of years old only dinosaur fossils sedimentary rocks on the tops of mountains