Mastering Chemistry: Key Concepts for Exam 1 Success
School
The City College of New York, CUNY**We aren't endorsed by this school
Course
CHEMISTRY 103
Subject
Chemistry
Date
Dec 12, 2024
Pages
4
Uploaded by MateMorning10180
Chemistry 103 Last Name: The City College of New York October 9, 2003 Exam 1 First Name: Prof. Yuying Gosser ID: 1.(5) 2 (12) 3 (5) 4 (12) 5 (12) 6 (15) 7 (15) 8 (24) Total Question 1 (5 pts) o % Y oile ) 3 RERE % 3 B T Round each of the following numbers to three significant figures, and express the result in standard exponential notation (a) 33,987.22 () -6.5559 Question 2 ( 12 pts ) How many protons, electrons, and neutrons are in the following atoms: (@) ®Ni (b) 40Ca2+
Question 3 (5 pts) Predict the chemical formula of the compounds formed by the pairs of ions: + 2- (@) Cu and S 1. CUSZ 2. CuS 3. Cu,S 4. CU282 5. CU382 (b) (Hg? and (COy* Hg(CO») Hg»(COs), Hg3(COs), Hg3(COs); Hg»(COs); Question 4 ( 12 pts) Balance the following chemical reaction and write net ionic equation for this reaction: Nl ot S e _ AgNOs(ag) + __ BaCly(ag) — _ AgCl(s) + ___ Ba(NOs)x(aq) Question 5 (12 pts) Balance the following equation and indicate oxidation number of iron in both reactant and product. _ Fe(NOs)aq) + __ Als) — __ Fe(s) + __ AlNO;s)s(aq)
Question 6 ( 15 pts) Only three isotopes of magnesium occur naturally, Magnesium-24 (mass = 23.9850 amu; abundance 78.99%), Magnesium-25 (mass = 24.9858 amu; abundance 10.00%) and Magnesium-26 (mass= 25.9826 amu; abundance 11.01%). Calculate the atomic weight (average atomic mass) of Mg. 'Question 7 ( 15 pts) Determine the empirical formula of the compound with the following compositions by mass: 24.5% Na, 14.9% Si, and 60.6% F
Question 8 (24 pts ) Sodium hydroxide reacts with carbon dioxide as follows: 2NaOH(s) + COx(g) — Na,COs(s) + HO(l) Which reagent is the limiting reactant when 1.70 mol NaOH and 1.00 mol CO, are allowed to react? How many moles of Na,CO; can form under these conditions? How many moles of the excess reactant remain after the completion of the reaction?