General Questions and Answers

An aqueous solution of the weak acid HA has pH 4 0 A solution of the salt NaA is added What happens to the pH of the solution A It decreases because additional acid has been added B It stays the same because the NaA solution is neutral C It increases because the conjugate base has been added D It increases slightly because the acid has been diluted

Which is a precipitation reaction A 2Cr s 6HNO aq 2Cr NO3 aq 3H g H B H PO aq 3KOH aq K PO4aq 3H O 1 C 3Ba NO3 aq 2Na PO4 aq Ba PO s 6NaNO aq D NaHCO aq HCl aq NaCl aq CO g H O 1

1 point each Find the measures of both angles NO CREDIT WITHOUT STEP BY STEP WORK 12 13 14 8r 6 51 5 9n 8 6n 7 Angle measures 4n 2 ver 3n 8 Angle measures 15 71 5 X 6r 4

23 What is the new molarity of a diluted HCI olution of 20 mL if the original acid had a volume of 10 mL and a molarity of 0 50 M a 1 0M b 0 75M c 0 50M d 0 25M

A pH 7 2 buffer is prepared by dissolving equimolar amounts of H PO4 and HPO4 in water 2 H PO4 H OHPO4 H O The addition of HCl to this buffer results in A a decrease in the H PO4 B an increase in the HPO2 C a decrease in the HPO42 D no change in the concentration of H PO4 or THPO 2 1

N Neutral Tastes sour H 108M Feels slippery pH 11 OH 1 x 10 M Ba OH H SO4 H 1 x 107M Tastes bitter pH 7 H 1 x 10 M Ca OH H3PO4 OH 1 x 10 3 M pH 4

Calculate the mass in grams of 12 5 moles of the compound H O O 125 grams O 180 grams O 212 grams O 225 grams

Given the following balanced chemical reaction CH4 g 2 O2 g CO g 2 H O 1 How many moles of O will be needed to produce 5 0 moles of CO from the correctly balanced reaction O 1 0 mole of O O 2 5 moles of O O 5 0 moles of O2 O 10 0 moles of O2

Which of the following processes is a chemical change O Drink mix is dissolved in water O Wood is broken down into sawdust O Water is heated and produces water vapor O Strips of paper are burned into dark gray ash

Which of the following elements is classified as a metalloid O Silicon Si O Xenon Xe O Copper Cu O Rubidium Rb

Potassium chlorate KCIO3 decomposes into potassium chloride KCI and oxygen gas O as shown in the equation below KClO3 s KCl s O g Which set of coefficients balances the chemical equation for this reaction O 1 1 3 O2 2 2 O2 2 3 O 2 3 6

Given the following equation 2 K O s 2 H O 1 O g 4 KOH aq How many grams of H O are needed to produce 0 5 moles of KOH molar mass of H O 18 0 g mole 0 5 grams 4 5 grams O9 grams 18 grams

Which statement best describes how a catalyst affects a chemical reaction O The temperature of the reaction will decrease O The activation energy of the reaction will decrease O The net energy released by the reaction will decrease O The frequency of molecular collisions during the reaction decreases

Below are the reactants of a single replacement single displacement reaction 2 NaBr Cl Which product s will this chemical reaction form O2 NaBrCl O2 NaCl Br O2 Na 2 ClBr 2 Na Cl Br2

3 12 05 How can the following cations be detected Write chemical equations and phenomen Hg2 Sb Bi Mn

Lee s friend says that a special cup will not let thermal energy pass through it Lee decides to test the cup He fills the cup with water and puts it on a hot plate Lee turns on the hot plate so it starts creating thermal energy He takes measurements every 2 minutes What should Lee do to see if thermal energy is passing through the cup O A He should measure the mass of the cup with a balance OB O C COD He should measure the temperature of the water with a thermometer He should measure the height of the cup with a meter stick He should measure the volume of the water using a graduated cylinder Unck Submit

Calculate the molarity of the two solutions The first solution contains 0 400 mol of NaOH in 1 45 L of solution molarity The second solution contains 13 3 g of NaCl in 885 mL of solution

1 What is the theoretical yield in grams of Ca OH 2 if 2 04 g of KOH reacts with 3 02 g of CaCl 2H O as shown by the below equation CaCl aq 2KOH aq Ca OH 2 s 2KCl aq of the calculation that converts the number of grams to moles for In the part CaCl 2H O the two water molecules must be included in the molar mass needed to convert grams to moles molar mass of CaCl2 2H O is 147 0 g mol What is the limiting reactant Limiting reactant Theoretical yield g

1120 If you start with 14 8 g of C3H8 and 3 44 g of O2 determine the number of moles of carbon dioxide produced and the number of grams of H O produced

Test 2 Name For the multiple choice questions write the letter of your choice in the boxes at right 11 3 pts each 1 Which of the following will contains the most hydrogen atoms c in Death Valley Ca d it would be the same at all locations a 20 molecules of CH3Cl b 1 mole of CH4 2 At which location would the atmospheric pressure be the greatest a at the top of Mt Whitney b in Redondo Beach c 21 molecules of hydrogen d 1 molecule of C12H22O12

Determine the name for each compound from its formulas SrBr Ni Sez

A solution is made using 180 3 g of hexane MM 86 18 g mol and 200 0 g of octane MM 114 2 g mol What is the molality of the hexane in the solution

Balance the given equations by inserting the appropriate coefficients chemical equation P 50 2P 05 chemical equation C H O CO H O Incorrect

How many milliliters mL of 0 450 M HCI must be added to neutralize 25 0 mL of 1 12 M KOH

For the reaction 2 NaOH H SO4 Na SO4 2H O how many grams of sulfuric acid H SO4 are needed to react completely with 20 7 g of sodium hydroxide NaOH mass

Determine the pH of a solution of HCl that has a molarity of 1 X 10 M

The insecticide DDT was found as a contaminate in a lake with a concentration of 8 75x10 5 M Safe levels of DDT are considered below 1 41x107 M DDT decomposes by first order kinetics with a rate constant of 0 0124 days1 How many days until the lake is considered safe from DDT contamination O225 days 2030 days 519 days 880 days 7 70 days

H OH Calculate the pH of a solution of NaOH with a molarity of 3 0 X 10 M Fi

20 How is soap different from detergent 21 What would the neutralization reaction product be for the following a Strong Acid Strong Base b Weak Acid Weak Base c Weak Base Strong Acid d Weak Acid Strong Base

Acid Base indicator the presence of on that changes

What is the pH of a solution if the H is 3 7 x 10 8M

4 Complete each of the following pressure conversions a 14 861 Torr to atm b 0 0551 Bar to kPa c 9 820 Psi to Torr d 28 3 Pa to psi

3RT Given that Vrms Vmolarmass velocity of nitrogen gas at 905 K and R 8 314 J mol K find the root mean square

Read the following lines from The Tell Tale Heart I knew that sound well too It was the beating of the old man s heart It increased my ury as the beating of a drum stimulates the soldier into courage hat things are compared in the lines above O The beating of the old man s heart and that of a drum O The beating of the drum and that of a soldier O The tapping of the soldier s boot and that of a drum The tapping of the soldier s boot and that

4 ion 5 6 Based on Octet rule calcium is most likely forms which a Ca b Cal c Ca6 d Ca Based on Octet rule Nitrogen most likely forms which ion a N b N c N6 The electronic configuration of 15 X 3 a Ne 3s 3p c Ne 3s 3p6 d N ion is b Ne 3s d Ne 3s 3p

What mass of SO is produced from the reaction of 31 5 g of S8 and 8 65 g of O

Disulfur dichloride S Cl is used to vulcanize rubber It can be made by treating molten sulfur with gaseous chlorine Starting with a mixture of 45 9 g of sulfur and 145 2 g of Cl What mass of S Cl2 in grams can be produced S Cl S Cl

Silver chloride precipitates from solution when AgNO3 is mixed with NaCl according to the reaction AgNO3 aq NaCl aq AgCl s NaNO3 aq Optional to submit work but strongly recommended because you will get NO credit if your entered answer is not exactly correct Work Partial Credit A Calculate the number of moles of each reactant when 0 175 L of 1 8 M NaCl is mixed with 0 190 L of 1 5 M AgNO3 Enter 2 sig figs with a space between your numerical answer and units moles Answer NaCl Enter your answer here Answer AgNO3 Enter your answer here limiting reactant

Elemental copper can be produced in the reaction below Cu O s C s 2 Cu s CO g When 7 6 grams of C 12 011 g mol reacted with 133 grams of Cu 0 143 10 g mol 77 4 grams of Cu 63 545 g mol was produced Optional to submit work but strongly recommended because you will get NO credit if your entered answer is not exactly correct Work Partial Credit A Determine the theoretical yield of Cu in grams Enter 3 sig figs with a space between your numerical answer and units grams Enter your answer here B Identify the limiting reactant Enter your answer here C What is the percent yield for this reaction Enter 3 sig figs with NO space between your numerical answer and units Enter your answer here

Consider the generic chemical equation 6A 4B7C Optional to submit work but strongly recommended because you will get NO credit if your entered answer is not exactly correct Work Partial Credit A What is the maximum number of moles of C that can be produced when 24 moles of A and 20 moles of B react B Enter your answer here Identify the limiting reactant Enter the letter only Enter your answer here C How many moles of excess reactant remain after the limiting reactant is used up Enter the number and units moles Enter your answer here

10 Points Calculate the maximum mass in grams of hydrogen gas H 2 016 g mol that can form when 57 5 grams of elemental iron Fe 55 933 g mol reacts with hydrochloric acid in the following balanced chemical equation Enter 3 sig figs with a space between your numerical answer and units grams 2 Fe s 6 HCl aq 2 FeCl3 aq 3 H g Optional to submit work but strongly recommended because you will get NO credit if your is not exactly correct Work Partial Credit

Q7 10 Points Calculate the maximum mass in grams of hydrogen gas H 2 016 g mol that can form when 57 5 grams of elemental iron Fe 55 933 g mol reacts with hydrochloric acid in the following balanced chemical equation Enter 3 sig figs with a space between your numerical answer and units grams 2 Fe s 6 HCl aq 2 FeCl3 aq 3 H g Optional to submit work but strongly recommended because you will get NO credit if your

When 35 00 grams of oxygen are completely reacted according to the chemical equation below how many grams of water could be produced 4NH3 502 4NO 6H O 19 71 grams 23 65 grams

What is the mass of 2 5 x 1025 atoms of helium 42 g 1 7 x 1048 g 166 g 17 g

Essay 6 topic Explain in your own words why do you think so many people in present day America believe that SCIENCE IS NOT IMPORTANT and that it is not worth the effort to learn Is this negative opinion of SCIENCE socially harmful or not Explain what you believe could be done to change these people s negative opinions of science T an citizen should

47 A beta particle is the equivalent to a Pure energy c Antimatter 48 If 2 half lives have passed what percentage of the original sample is still remaining a 75 b 50 d 12 5 a 25 b A Helium atom d A High energy electron 49 Which of the following defines or is an example of nuclear fusion a Nucleus of an atom splits to form two new isotopes b 2 H isotopes combine to form a He atom neutron and energy c Chain reaction of U 235 occuring d Neutron bombarding a heavy nucleus D Which of the following would describe a chain reaction a Isotopes combining to form a new nucleus and releasing lots of energy b Neutron bombarding a heavy nucleus producing multiple neutrons and 2 new isotopes c Nuclear fission d A B e B C Enoiluhen to algmise ne al piwoltol or to risin

people s negative Essay 7 topic Based on what you have learned in this course and in other college courses what do you believe any ordinary citizen should understand about the scientific concept of energy Why is it important that ordinary people understand this science concept

When the volume of a gas increases pressure decreases Ostays constant increases

5 11 x 1023 atoms of lithium Li is equal to how many moles bles 1 18 moles 0 849 moles 1 34 mole

What is the right ratio of chemicals for the BCE Balanced Chemical Equation Ni 02 Ni 03 4 3 4 4 3 2 3 4 1 4 1 2