Chemistry Mid-term Exam Questions

Anonymous
timer Asked: Apr 10th, 2019
account_balance_wallet $19.99

Question Description

It is important that you provide answers in your own words. Please focus only on information from the text/eBook to create your own solutions. Please do not use direct information from an outside source (especially copying and pasting from an “answer” website). Use of direct information from an outside source is against school policy. All answers will be checked for plagiarism. Instances of plagiarism can result in probation or possible dismissal from the school.

Please be sure to follow all guidelines (number of sentences/showing all calculations) and to provide the correct metric units of measure. All questions are 3.33 points (.33 point for units).

Unformatted Attachment Preview

Chemistry Mid-term Exam Version 11/2016 Name: Student number: Directions: It is important that you provide answers in your own words. Please focus only on information from the text/eBook to create your own solutions. Please do not use direct information from an outside source (especially copying and pasting from an “answer” website). Use of direct information from an outside source is against school policy. All answers will be checked for plagiarism. Instances of plagiarism can result in probation or possible dismissal from the school. Please be sure to follow all guidelines (number of sentences/showing all calculations) and to provide the correct metric units of measure. All questions are 3.33 points (.33 point for units). 1. Experimental Design: From the work you have done this semester, choose a topic and design an experiment you would be able to perform. In your design (1) state your hypothesis, (2) identify your dependent and (3) independent variables, (4) your control conditions and (5) describe your experimental procedure. You do NOT have to actually complete the experiment, just describe it with the application of the terms above. 2. Perform this operation and report the answer to the correct number of significant figures: What is the mass of a cube of aluminum that is 4.0 cm on each edge? The density of aluminum is 2.7 g/cm3. Show all calculations leading to an answer. 3. Explain why a model of the atom is crucial to understanding chemistry and in explaining the behavior of matter. Use 3 - 4 sentences in your explanation. 4. What parts of Dalton’s atomic theory no longer agree with the current picture of the current picture of the atom? Provide an answer using at least 3 to 4 complete content related sentences in your own words. 5. If an element has 12 protons and 17 neutrons, how many electrons must it have? 6. Why are the atomic masses of elements usually decimal numbers? Provide an answer using 3 – 4 sentences in your own words. 7. In 3 – 4 sentences and in your own words describe how Mendeleev’s periodic table differs from Moseley’s. 8. What is the electron configuration of the element with 27 protons? 9. How many electrons are in the highest energy orbital of the element copper? 10. How many dots should be indicated in the electron dot structure of arsenic? 11. Why is the first ionization energy of a nonmetal much higher than that of an alkali metal in its same period? Provide an answer using 3 – 4 sentences in your own words. 12. Why do compounds with strong intermolecular attractive forces have higher boiling points than compounds with weak intermolecular attractive forces? Provide an answer using 3 – 4 sentences and in your own words. 13. Write the formula for iron (III) sulfate. 14. What is the reason the group 13 metals have a typical charge of 3+? 15. Why does one mole of carbon atoms have a smaller mass than one mole of sulfur atoms? 16. What is the percentage of nitrogen in N2O? Show all calculations leading to an answer. 17. How many non-bonding electrons does phosphorus have? 18. Complete and balance this reaction: sulfuric acid reacts with barium chloride 19. Identify the precipitate in this reaction: calcium nitrate reacts with sodium phosphate. 20. The following is a Limiting Reactant problem: Magnesium nitride is formed in the reaction of magnesium metal with nitrogen gas in this reaction: 3 Mg(s) + N2(g) → Mg3N2(s) How many grams of product are formed from 2.0 mol of N2 (g) and 8.0 mol of Mg(s)? Show all calculations leading to an answer. 21. List 3 indicators of a chemical change. a. _____________________ b. ____________________ c. ____________________ 22. Check the following problem for errors. If you find an error, identify it, tell why it is an error and correct the error solving the problem correctly. Convert 0.45 g zinc hydroxide to moles. (Hint: there are errors) 0.65 g ZnOH 82.41 mol 6.02X1023 g = 3.22 X 10 25 mol 23. What is an ion? Explain how ions form. Distinguish between a cation and an anion. Be sure to use at least 3 to 4 complete content related sentences in your explanation. 24. Write the symbol for the ion formed when each element gains electrons and attains a noble-gas electron configuration. a. Br b. H c. Se 25. Name each of the compounds. There are ionic, covalent and acid/base compounds in the list. a. N2H4 b. PI3 c. LiOH 26. Classify each chemical equation as a combination/synthesis , decomposition, single replacement, double replacement, or combustion. a. Pb(s) + Hg2SO4(s) → PbSO4(s) +2 Hg(l) b. NaCl(aq) + AgNO3(aq) → AgCl(s) + NaNO3(aq) c. 2 H20(l)→2 H2(g) + 02(g) 27. Find the molar mass of nitric acid (HNO3). 28. Avogadro’s number refers to ___. a. the maximum number of electrons that all of an atom’s energy levels can accommodate b. the number of protons and neutrons that can fit in the shells of an atom’s nucleus c. the number of particles in one mole of a substance d. the number of particles in exactly 1.0 g of a substance 29. How many moles of oxygen atoms are in 1.5 moles of CO2? (Sc2c) a. 1 mol b. 1.5 mol 30. What is the mass of 0.28 mol of iron ? c. 2 mol d. 3 mol ...
Purchase answer to see full attachment

Tutor Answer

SkilledTutorZiss
School: Carnegie Mellon University

Attached.

1. Combustion. My hypothesis is that when you spray sunscreen (TiO2) in the flame of a
lighter (C10H4) will cause the same effects as a blow torch. The spray sunscreen is
dependent on the flame of the lighter. The spray sunscreen is dependent. The flame of the
lighter is independent. The controlled conditions are how much sunscreen you spray and
how long you allow the flame of the lighter to burn. First, you will find a lighter and a
spray bottle of sunscreen, then you will light the lighter so there is a flame (C10H4) safely
you will face the spray sunscreen away from you and spray the sunscreen (TiO2) onto the
flame and you will see the same effects as a blow torch.

Volume of cube = 4.0 3 = 64cm 3
Density = 2.7 g / cm 3
2. Mass = ?
Mass = Density  Volume
= 64cm 3  2.7 g / cm 3 = 170 g
3.
When you have a model of an atom it allows you to identify the number of protons,
neutrons, and electrons. With that information we are able to find out the name of the
element, the mass and much more. Without a model you would not be able to find this
information, therefore not be able to iden...

flag Report DMCA
Review

Anonymous
Top quality work from this guy! I'll be back!

Brown University





1271 Tutors

California Institute of Technology




2131 Tutors

Carnegie Mellon University




982 Tutors

Columbia University





1256 Tutors

Dartmouth University





2113 Tutors

Emory University





2279 Tutors

Harvard University





599 Tutors

Massachusetts Institute of Technology



2319 Tutors

New York University





1645 Tutors

Notre Dam University





1911 Tutors

Oklahoma University





2122 Tutors

Pennsylvania State University





932 Tutors

Princeton University





1211 Tutors

Stanford University





983 Tutors

University of California





1282 Tutors

Oxford University





123 Tutors

Yale University





2325 Tutors