Which is the equation of a circle with its center at (-4,2) and a radius of 4?

Select one:

a. (x+4) 2 + (y-2) 2 = 16

b. (x-4) 2 + (y+2) 2 = 16

c. (x-4) 2 + (y+2) 2 = 4

d. (x+4) 2 + (y-2) 2 = 4

If a substance cannot be seperated physically or chemically, it is?

Which of the following is an example of a physical property? A) reacts with metals B) hardness C) changes color when burned D) tarnishes

Rank the following elements by effective nuclear charge, Zeff, for a valence electron. F LI Be B N

What information would you need in order to convert Molarity to % by volume

How is sound energy produced? A. by vibrating objects B. by stationary objects C. by temperature differences D. by objects being heated

Shawn wants to buy a pair of gloves online. She needs to know the length of her hand in order to choose the correct size. Which Sl unit would be most appropriate for describing the length of her hand? A. Kilograms B. Milliliters C. Kilometers D.

Knowing the reactions between hydrogen gas and oxygen gas to form water is exothermic which would you say is greater: the average bond energies for hydrogen and oxygen or the bond energies for water? Explain.

Why would a C-O bond have only provide 358 kJ/mol each while C=O provides 799 kJ/mol? Explain in detail.

Transition metals, like copper, are found in many types of biological molecules where it is common for metals to have deviations from ideal bond angles.

How many moles of aluminum metal are required to produce 4.04 L of hydrogen gas at 1.11 atm and 27 °C by reaction with HCl? 2 Al (s) + 6 HCl (aq) → 2 AlCl3 (aq) + 3 H2 (g)