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A 25.0 mL sample of HBr is neutralized by reaction with 20.0 mL of 3.00 M KOH.  What is the concentration of HBr is the unknown sample? *hint- find the concentration of the base first.

.  Based on electronegativities, a P-Cl bond is:

A sample of metal has a mass of [m] grams.  What is this mass in milligrams?

A solution has a mass of [x] grams, and a volume of [y] mL.  What is the density (g/mL) of this solution, reported to the correct number of significant digits?

An aqueous solution is found to have an H+ concentration of 7.8 x 10-2 M.  What is the concentration of OH- in this solution?

The following reaction is an example of an ___ reaction. 2 N2(g) + O2(g) → 2 N2O (g)             ΔHrxn = +163.2 kJ

What is the frequency of a photon of light with a wavelength of 615 nm?

Using VSEPR , fill in the table. Attach an image of your work- must be handwritten.  Lewis Dot Structure # bonded groups #lone pairs Molecular Shape CH4 CCl2O

A chemist carries out this reaction in the laboratory, using [x] grams of zinc and an excess of sulfur:  She isolated [y] g of ZnS. Zn + S –> ZnS   Using the balanced equation, calculate the percent yield the chemist retrieved from the reaction.   What is her percent yield for this reaction?   percent yield= (actual yield)/(theo yield) *100%

A 1.0 gram sample of a candy bar was placed in a bomb calorimeter with a heat capacity of 3.54 kcal/°C. The sample was completely burned, causing the temperature of the calorimeter to rise by 1.36 °C.   How many kilocalories of energy were stored in the candy bar?    Make sure to show all your work- No work = no credit