How many of the following names are correct? PCl5 potassium pentachloride NaCN sodium cyanide KrF4 krypton tetrafluoride Fe(NO3)2 iron (II) nitrate  

A sample of pure lithium carbonate contains 44.3% lithium by mass. What is the % lithium by mass in a sample of pure lithium carbonate that has twice the mass of the first sample?

The compound, NO6, is named

Which of the following represent isotopes of the same element? (X is just a placeholder) A: X B: X C: X D: X  

An element has two naturally occurring isotopes. One has an abundance of 35.4% and an isotopic mass of 184.953 amu, and the other has an abundance of 64.6% and a mass of 186.956 amu. What is the average atomic mass of the element?

A piece of plastic weighing 1.157 g has a volume of 1.48 cm3. A piece of wood has the same volume but weighs 3.85 g. Which of the two pieces will float on water? The density of water is 0.997 g/cm3. 

What is the molarity concentration of FeBr3 in a solution prepared by dissolving 10.0 g of FeBr3 in enough water to make 550 mL of solution?

Choose the best verb for this sentence.  Conjugate the verb into the appropriate form.  Write only the verb form below.  Hint:  there will be 2 words in your answer.  Follow the model. Modelo:  Juan _______  ______________ (levantarse / secarse) después de ducharse.  se seca Pedro y Pablo ________ ______________ (peinarse / lavarse) las manos antes de comer.

Hay un perro grande afuera (outside) y no quiero salir.  Es porque tengo

Choose the best verb for this sentence.  Conjugate the verb into the appropriate form.  Write only the verb form below.  Hint:  there will be 2 words in your answer.  Follow the model. Modelo:  Juan _______  ______________ (levantarse / secarse) después de ducharse.  se seca Marta _____ ______________ (cepillarse / ponerse) los dientes.