Iron undergoes oxidation to form iron rust. The flaking rust exposes fresh iron surface to the environment, allowing the rusting process to continue. What is the coefficient of Fe2O3 after balancing the following chemical equation? Fe (s) + O2 (g) → Fe2O3 (s)

The gas mileage of a car is 22 km/L. Convert the mileage to miles per gallon. (Given: 1 km = 0.6214 mi; 1 gal = 3.785 L)

While identifying the unknown liquid, which of the following physical properties wasn’t used?

Determine the number of moles of oxygen in 1.60 moles of sodium hydrogen phosphate (Given molecular formula: Na2HPO4)  

Consider the recipe: 2 cups flour + 3 eggs + 1 tbsp oil à 4 pancakes What is the theoretical yield if you have 5 cups of flour, 9 eggs, and 3 tbsp oil?

A scientific theory is a model for the way nature is and tries to explain not merely what nature does, but why. Which of the following statements represent a theory?

How many electrons are present in O2- ion? (Given: Atomic number (Z) of oxygen is 8)

Na and K belong to group 1A. Na reacts with Cl2 and forms NaCl as per the following equation.  2Na (s) + Cl2 (g) → 2NaCl (s) What is the product formed when K reacts with Cl2 gas?

How many He atoms are contained in 2.36 moles of He? (Given: 1 mol = 6.022×1023)

The formula of aluminum sulfate is (Given ions: Al3+ and SO42-)