Chem119-935am-quiz9-key

A student weights out 3 samples of KHP to standardize a NaOH solution and added 100 mL to each flask. They ran out of time and placed the flasks in the storage cabinet for the week. The following week the flasks only contained 85 mL of solution. What should the student do? O a) Add 15 mL of water and continue. KHP does not evaporate. b) Start over. Some of the acid evaporated O c) Decrease the volume in the burette by 15 mL as well. d) Add more indicator to account for the decreased volume.

The concentration of Br− in a sample of seawater is 7.3 ⋅ 10−4 M. If a liter of seawater has a mass of 1.0 kg, the concentration of Br− is ________ ppm.

What volume in L of a 0.32M Mg(NO:)2 solution contains 45 g of Mg(NO:): ? X STARTING AMOUNT ADD FACTOR ANSWER RESET *( ) 148.33 86.32 10 45 1 210.34 6.022 x 1023 0.097 0.95 0.32 140 0.30 L mL mol Mg(NOs): M Mg(NOs): g Mg(NOs)2 g Mg(NO:)»/mol

Please answer Parts 2 and 3

Convert the experimental glucose concentration (provided in the table below) from mM (millimolar) to g/100 mL. Write a step-by-step guide with key words for the Chem 2 students on how to do these calculations. You can use diagrams, a table or just type the steps out. Ensure the steps are clearly written and easy to follow  Drink # Glucose Concentration in mM 1 2.340 mM 2 0.288 mM 3 3.500 mM 4 0.136 mM 5 1.673 mM

Part 1 – Preparation of CaCO3(s)  The following is a procedure that was theoretically performed by a student. Read through the procedure and answer the questions below. A 10.0 mL graduated cylinder to measure 10.0 mL of a 1.00 M CaCl2 solution into an initially empty 50.0 mL beaker. A 50.0 mL graduated cylinder was then used to measure out 25.0 mL of 0.500 M K2CO3. This K2CO3 solution was then added to the beaker containing the CaCl2 The solution became cloudy, and the student concluded that a precipitate must have formed. Write a balanced chemical reaction below, including phases, and identify the chemical formula of the precipitate:   Answer the questions below as part of Data Analysis.  1. What is the actual yield of the product? 2. Using stoichiometry, calculate the limiting reactant, and the theoretical yield (the mass of CaCO3 product) for the reaction. 3. Determine the percent yield of the reaction.

13. A 800.0 L sample of drinking water is found to contain 2.00 mg of arsenic. What is the concentration (in M) of arsenic in the sample? A: 3.34 x 10-8

AaBbCcDc AaBbCcDc AaBbCC AABBCCC A aB 前。 1 Normal 1 No Spac... Heading 1 Heading 2 Title Paragraph A sample of potassium bicarbonate (KHCO3) was reacted with HCl to produce KCl. The following Styles 7 data was collected. Mass of beaker 28.43 g Mass of beaker + KHCO3 36.95 g Volume of HC1 12.0 mL Concentration of HCl 9.0 M Mass of beaker +residue (KCI) 33.82 g Calculate the following quantities. Show calculations where requested: Mass of KHCO3 Mass of residue Mass of 1 mol of KHCO3 No. of moles of KHCO3 used Show calculations below No. of moles of HCl added Show calculations below: Assuming KHCO3 is the limiting reactant, how many grams of KCl can be formed? Show calculations below: Assuming HCl is the limitingʻreactant, how many grams of KCl can be formed? Show calculations below: Which reactant is limiting? Which reactant is excess? Actual yield of KCI: Theoretical yield of KCl: Percent yield of KCl: W

Part 1,2and3

how did you get the dilution factor? is the dilution factor 9? or 91?

com/alekscgi/x/Isl.exe/1o_u-IgNslkr/J8P3JH-IBEWe Maps O MEASUREMENT Lindsay Adding or subtracting and multiplying or dividing measurements chemistry student must write down in her lab notebook the concentration of a solution of sodium hydroxide. The concentration of a solution equals the mass what's dissolved divided by the total volume of the solution. re's how the student prepared the solution: • The label on the graduated cylinder says: empty weight: 6.050 g dlo - She put some solid sodium hydroxide into the graduated cylinder and weighed it. With the sodium hydroxide added, the cylinder weighed 96.4 g. - She added water to the graduated cylinder and dissolved the sodium hydroxide completely. Then she read the total volume of the solution from the markings on the graduated cylinder. The total volume of the solution was 151.66 mL. Ar at concentration should the student write down in her lab notebook? Be sure your answer has the correct number of significant digits. -1 gmL

A student takes a sample of KOH solution and dilutes it to 100.00 mL of water. The student determines that the diluted solution is 0.024 M KOH, but has forgotten to record the volume of the original sample. The concentration of the original solution is 3.685 M. What was the volume of the original sample (in mL)? Answer to 2 decimal places Read about significant figures and rounding in the Helpful Resources page! Do not include units when reporting your answer Use standard notation or scientific notation as accepted by blackboard e.g. 0.001 or 1E-3, not 1 x 10^-3

2- A solution of sugar contains 35 grams of sucrose, C12H22O11 in 100 mL of solution. What is the concentration of the solution in grams/Liter?

A chemist has three different acid solutions. The first acid solution contains 20% acid, the second contains 40% and the third contains 85%. They want to use all three solutions to obtain a mixture of 140 liters containing 35% acid, using 2 times as much of the 85% solution as the 40% solution. How many liters of each solution should be used? The chemist should use liters of 20% solution, liters of 40% solution, and liters of 85% solution.

Pp

Chem101 -> A neutral solution of water at a particular temperature has a concentration of OH- of 7.5 x 10-7 M. What is Kw at this temperature? CHEM 101 0pp dd

Equal volumes of Solutions 2 and 3 were mixed in the lab. Suggest a measurement that could be made in the lab to provide evidence that a chemical reaction occurred when Solutions 2 and 3 were mixed.