A 31.5 mL aliquot of H2SO4 (aq) of unknown concentration was titrated with 0.134 M NaOH (aq). It took 23.9 mL of the base to reach the endpoint of the titration. What is the molarity of the acid? Must show your work on scratch paper to receive credit. 2 NaOH(aq)  + H2SO4(aq)   →  Na2SO4(aq)  + 2 H2O­(l)

When 6.00 g of CS2 (MM = 76.13 g/mol) gas react with 10.0 g of Cl2 (MM = 70.90 g/mol) gas in the following reaction: CS2(g) + 3 Cl2(g) → CCl4(l) + S2Cl2(l) What is the limiting reactant? How many grams of CCl4 (153.81 g/mol) are produced? How many grams of the excess reactant are left? If 6.50 g of CCl4 are produced, what is the percent yield of the reaction? Must show your work on scratch paper to receive credit.

Many metals react with oxygen gas to form the metal oxide. For example, calcium reacts as follows: 2Ca(s) + O2(g) ⟶ 2CaO(s) You wish to calculate the mass (g) of calcium oxide that can be prepared from 4.20 g of Ca (MM = 40.08 g/mol) and 2.80 g of O2(MM = 32.00 g/mol). Which is the limiting reactant? How many grams of CaO (MM = 56.08 g/mol) can be produced? How many grams are left of the excess reactant? If 5.00 g of CaO were obtained, what is the percent yield of the reaction? Must show your work on scratch paper to receive credit.

Given the data:  Ca(s) + ½ O2(g) → CaO(s)  ΔH = −635.1 kJ CaCO3(s) → CaO(s) + CO2(g) ΔH = 178.3 kJ using Hess’s Law the ∆H for the reaction below is [a] kJ:2 Ca(s) + O2(g) + 2 CO2(g) →  2 CaCO3(s)Must show your work (scratch paper) to receive credit.

Nitric acid is neutralized by the reaction with calcium hydroxide by the following reaction: Ca(OH)2(s) + 2 HNO3(aq) →  Ca(NO3)2(aq) +  2 H2O(l) What volume (L) of 0.250 M HNO3 is required to neutralize 17.5 g Ca(OH)2? Must show your work on scratch paper to receive credit.

The element X has three naturally occurring isotopes. The isotopic masses (amu) and % abundances of the isotopes are given in the table below. The average atomic mass of the element is ________ amu.             Isotope Abundance (%) Mass 164X 30.60 159.37 164X 15.79 162.79 164X 53.61 163.92  

How many electrons, protons, and neutrons are present in the following isotopes  protons: [a], neutrons: [b], electrons: [c] 

The following reaction:  calcium carbonate producing calcium oxide and carbon dioxide, is an example of 

When solutions of an acid and a base are reacted, the products are    

How many grams of hydrogen gas would be produced when 6.0 grams of magnesium react with excess of an acid?   Mg + 2 HCl → MgCl2 + H2