How many moles of hydrogen are required to produce 45 moles of water

I am so lost, and suggestions to how I can solve this? A sample of nickel (specific heat capacity 0.446J/goC) is heated to 255.5oC and placed in a coffee cup calorimeter containing 250.0 g of water at a temperature of 20.0oC.

Which compound (s) is (are) bonded ironically A. KI B. CO C. CO2 D. CaO Check all that apply

When two pure substances are combined so that each of the pure substances retains its own properties, what is the result

Which element has the largest atomic radius? A.) As B.) N C.) P D.) Sb

If the frequency of a wave is 68 hertz then the period of the wave is going to be

How does the state of matter affect the speed of sound

Which of the processes is exothermic? 1. evaporation of alcohol 2. sublimation of iodine 3. solidification of volcanic lava 4. burning of paper

The maximum amount of solute that dissolves in a given amount of solvent and forms a stable solution is called the

Which determines the chemical properties of minerals? A. cleavage B. crystal shape C. type of atoms D. luster

Why is pure orange juice a mixture?