For the reaction: 2H2O (l) + 137 kcal → 2H2 (g) + O2 (g) How many kcal are needed to form 2.00 grams of H2 (g)?    

Which reaction below (A – E) is a double replacement reaction? A. CuCO3 –> CuO + CO2 B. 2 NaCl + Pb(NO3)2 –> 2 NaNO3 + PbCl2 C. CH4 + O2 –> CO2 + H2O D. Cu + 2 AgNO3 –> 2 Ag + Cu(NO3)2 E. C + 2 Cl2 –> CCl4

In the reaction of nitrogen gas, N2, with hydrogen gas, H2, to form ammonia gas, NH3 , how many moles of hydrogen are needed to react with two moles of nitrogen? (Hint: write a balanced equation)  

Colmar, Inc. incurred the following costs for the month of June in manufacturing gardening tools. Wood handles and metal parts used $  156,000  Advertising $  15,000 Salespersons’ salaries and commissions 22,000  Insurance on factory 13,000 Labor costs for tool assemblers 85,000  Factory manager salary 9,000 Factory equipment depreciation 27,000  Factory building rent 39,000 Office supplies 14,000  Factory utilities 11,000   Total production costs are ____________________

In the ionic compound CaCl2, the charge of the calcium ion is  

If the electronegativity difference between elements X and Y is 0.8, the bond between the elements X-Y is

Which type of radiation is most damaging if inhaled or ingested?                                                     

What is the molar mass of copper(II) phosphate  Cu3(PO4)2  

When 2.0 grams of Mg3N2 are allowed to react, how many moles of H2O also react? Given: Mg3N2(s) + 6H2O (l) → 3Mg(OH)2(s) + 2NH3(g)  

The correct formula for an ionic compound formed from the elements Mg and Br is