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M2: Exam - Requires Respondus
LockDown Browser + Webcam
Due No due date Points 100 Questions 10
Time Limit 120 Minutes
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Instructions
Please read the following before beginning the exam: You must show your work for calculations or give an explanation for short answer questions in order to receive credit. You may only use the methods and explanations provided by this course for your answers. The use of a method or explanation that was not taught in this course is a violation of the Academic Integrity Policy. You MUST only use the Periodic Table provided within the exam. You MUST only use the equation bank that is provided within the exam. The use of printed versions of the Periodic Table and equation bank will be considered a violation of the Academic Integrity Policy. Any equation or constant used on an exam that is not from the equation bank and is different from the method taught in this course will be considered an outside source and a violation of the Academic Integrity Policy. During module exams you may not use any outside source of information such as the module, problem sets, notes, Internet, tutor, etc.
* Some questions not yet graded Attempt History Attempt Time LATEST Attempt 1 (https://portagelearning.instructure.com/courses/956/quizzes/24872/history? version=1) 112 minutes Score for this quiz: 0 out of 100 * Submitted Oct 31 at 3:22pm This attempt took 112 minutes. You may ONLY copy and paste from within the exam itself, from the equation bank, or from the provided calculator but not from an outside source. The only items you should have in front of you are your computer, 1-2 pieces of blank scratch paper, a calculator (non-cell phone), and a pen/pencil. Question 1^ Not yet graded^ / 10^ pts You may find the following resources helpful: Scientific Calculator (https://www.desmos.com/scientific) Periodic Table (https://previous.nursingabc.com/upload/images/Help_file_pic Equation Table (https://previous.nursingabc.com/upload/CHEM104%20- %20Equation%20Bank.pdf)
MgCl Salt Contains Metal (Mg) + Nonmetal (Cl) HClO Acid Contains H + Polyatomic group (ClO ) Cu(OH) Base Contains Metal (Cu) + OH Polyatomic group 2 4 4 2 Question 2^ Not yet graded^ / 10^ pts You may find the following resources helpful: Scientific Calculator (https://www.desmos.com/scientific) Periodic Table (https://previous.nursingabc.com/upload/images/Help_file_pic Equation Table (https://previous.nursingabc.com/upload/CHEM104%20- %20Equation%20Bank.pdf) For the Brønsted-Lowry acid base reactions shown below, list the stronger acid, stronger base, weaker acid and weaker base in the answer blanks provided: NH + H PO NH + H PO Stronger acid: Stronger base: 4
2 4
Your Answer: Weaker acid: Weaker base: the arrows tell us the answer like if it has a longer arrow it means it is stronger acid and base. shorter arrows means it gives us the lesser reaction. Stronger acid: H PO Stronger base: NH weaker acid: NH + weaker base: H PO - 3 4 3 4 2 4
Your Answer: Equation Table (https://previous.nursingabc.com/upload/CHEM104%20- %20Equation%20Bank.pdf) For the compounds shown below, choose the stronger acid, explain why it is the stronger acid and write the formula of its conjugate base in the answer blank: H O or H S or H Te Stronger acid is: Explanation: Formula of conjugate base of the stronger acid: 2 2 2 Stronger acid is: H O Explaination: We look at electronegativity so like the if we look at the table the ones upper have higher electrongativity than the ones below. hopefully i make sense. I am looking at (O, S,Te) O is higher out of the three. O makes more H-O bond more polar more like to form H+. Formula of conjugate base of the stronger acid: OH- 2
H O or H S or H Te Stronger acid is: H Te Explanation: Te is the largest atom (of O, S or Te) which makes the H-Te bond weakest and most likely to form H Formula of conjugate base of the stronger acid: conjugate base of H Te is HTe 2 2 2 2
2
- Question 4^ Not yet graded^ / 10^ pts Your Answer: You may find the following resources helpful: Scientific Calculator (https://www.desmos.com/scientific) Periodic Table (https://previous.nursingabc.com/upload/images/Help_file_pic Equation Table (https://previous.nursingabc.com/upload/CHEM104%20- %20Equation%20Bank.pdf) Show the calculation of the [H ] and pH of a 0.00198 M solution of the strong acid H SO.
2 4 [H+]=2x[H2SO4]= 0.00396M pH=-log(0.00396)=2.
( H SO is the acid and Na OH is the base) M x mL / 1000 x S / S = g / MW M x 22.3 / 1000 x 2 / 1 = 0.304 / 39. M = 0.170 M 2 4 a a a b b b a H2SO Question 6^ Not yet graded^ / 10^ pts Your Answer: You may find the following resources helpful: Scientific Calculator (https://www.desmos.com/scientific) Periodic Table (https://previous.nursingabc.com/upload/images/Help_file_pic Equation Table (https://previous.nursingabc.com/upload/CHEM104%20- %20Equation%20Bank.pdf) Show the calculation of the [H ], pH and % ionization for 0.389 M acetic acid (HC H O ) HC H O H + C H O K = 1.8 x 10
2 3 2 2 3 2
2 3 2
a
K= products / reactants K= [H+] [C2H3O2=]/[HC2H3O2]=
-x. +x. +x 0.389-x. x x 1.85x10^-5/0.389-x=1.8x10^-5/0. x^2= 7.002x10^-6=0.0026=H+ pH=-log [H+]=-log =2. % ionization = [C2H3O2-] [HC2H3O2]x100= 0.0026/0.389x100= 0.67% HC H O H + C H O K = 1.8 x 10 = [H ] [C H O ] = (x) (x) 1.8 x 10 = (x) (x) [HC H O ] (0.389 - x) (0.389) x = (1.8 x 10 ) (0.389) x = 2.65 x 10 = [H ] pH = - log [H ] = - log (2.65 x 10 ) = 2. % ionization = [C H O ] x 100 = (2.65 x 10 ) x 100 = 0.68 % [HC H O ] (0.389) 2 3 2
2 3 2
a -5 + 2 3 2
2 3 2 2 - -3 + +
2 3 2
2 3 2
Your Answer: You may find the following resources helpful: Scientific Calculator (https://www.desmos.com/scientific) Periodic Table (https://previous.nursingabc.com/upload/images/Help_file_pic Equation Table (https://previous.nursingabc.com/upload/CHEM104%20- %20Equation%20Bank.pdf) Show calculation of the pH of a buffer prepared by mixing 0.125 M NaC H O and 0.075 M HC H O. HC H O H + C H O K = 1.8 x 10 2 3 2 2 3 2 2 3 2
2 3 2
a
HC2H3O2. H+ C2H302- 0.075 0 0. -x. +x. +x 0.075-x 0+x. 0.125-x K= products over reactants K= [H+] [C2H3O2]/ [HC2H3O2] K= [0+X] [0.125-X]/ [0.075-X] = 1.6x/ 1.8 x 10 ^-5 ( that is an exponent hopefully you can see the tool wont let me do it the normal way)
= 88888.88 [OH-] I do not like this question i tried multiple times its not scientific notation and its a huge amount i dont like the given values pOH=-log [OH-]=- log (88888.88 )= -4. pH 14-OH= 14- -4.95 = 18. worst question ever with the worse values given not fair at all K = 1.8 x 10 = [H ] [C H O ] = (x) (0.1250 + x) 1.8 x 10 = (x) (0.1250) [HC H O ] (0.0750 - x) (0.0750) x = (1.8 x 10 ) (0.0750) / 0. x = 1.08 x 10 = [H ] pH = - log [H ] = - log (1.08 x 10 ) = 4. a -5 + 2 3 2
2 3 2
-5 + +
Question 9^ Not yet graded^ / 10^ pts You may find the following resources helpful: Scientific Calculator (https://www.desmos.com/scientific) Periodic Table (https://previous.nursingabc.com/upload/images/Help_file_pic Equation Table (https://portagelearning.instructure.com/courses/956/files/
HC H O H + C H O
K = 1.8 x 10 = [H ] [C H O ] = (x) (0.
- x) 1.8 x 10 = (x) (0.090) [HC H O ] (0.
- x) (0.110) x = (1.8 x 10 ) (0.110) / 0. x = 2.20 x 10 = [H ] pH = - log [H ] = - log (2.20 x 10 ) = 4. 2 3 2 + 2 3 2 - a -5 + 2 3 2
2 3 2
-5 + +
Question 10^ Not yet graded^ / 10^ pts You may find the following resources helpful: Scientific Calculator (https://www.desmos.com/scientific) Periodic Table (https://previous.nursingabc.com/upload/images/Help_file_pic Equation Table (https://previous.nursingabc.com/upload/CHEM104%20- %20Equation%20Bank.pdf) List and explain what type of acid and base are involved in the titration curve below and select an appropriate indicator to be used in this titration from the list below.
Your Answer: pH Range of Indicator Color Change Methyl violet 0.0 - 1. Phenolphthalein 8.0 - 9. Alizarin yellow R 10.1 - 12. So like this thing looks like its equivalence point is at pH 7. this is a titration of a strong acid strong base. the rapid rise thing happens like between pH 3 and pH 11. The indicator used is phenolphthalein because of its rande 8.0 -9.8. we can't use methylviolet nor alizarin yellow R.
