What coefficient placed in front of O2 is needed to complete balancing of the following equation? C5H8 (l) + ? O2 (g) –> 5 CO2(g) + 4 H2O (g)

What volume of 80% NaOH is required to make 50 ml of 6% NaOH?

How many kcal are produced when 32.0 CH4 g reacts in the reaction shown below? CH4 (g) + 2 O2 (g) –> 2 H2O (g) + 218 kcal

Consider a neutral atom with 30 protons and 34 neutrons. The mass number for this atom is:

The number of neutrons in an isotope of an atom is equal to

Silicon has three naturally occurring isotopes: Si-28 (mass = 28.0 amu); Si-29 (mass = 29.0 amu), and Si-30 (mass = 30.0 amu). If the average atomic mass of silicon is 29.1 amu, which isotope is the most abundant?

The correct conversion factor to calculate the number of Liters in 5,687 ml is:

A rock rolling down a hill is an example of

A slice of pizza contains 29 g of carbohydrate, 13 g of protein and an unknown amount of fat. If the pizza contains 280 kcal, how many grams of fat are present? (The caloric values for foods are 4.0 kcal/g for carbohydrate, 4.0 kcal/g for protein, and 9.0 kcal/g for fat.)

Bromine has a freezing point of -7˚C and a boiling point of 60˚C.  Indicate the state or change of state occurring at -7˚C.