University:
San Jose State University
Course:
CHEM 10 | Chemical Calculations and Concepts
Academic year:

2022
Views:

247

Pages:

2
Author:

Cyncuncewc3b4

Exam 1 (Section 3) (30 points, 1.5 pts each) Instructions: Give the formula or name for the following: (Spelling counts! - 1 point if close but spelled wrong) (do not dwell upon these, either you know 'em or you don't!) ammonium chlorate NH₄ClO₃ Strontium hydroxide Sr(OH)₂ lithium carbonate Li₂CO₃ Calcium phosphate Ca₃(PO₄)₂ perchloric acid HClO₄(aq) Aluminum Sulfate Al₂(SO₄)₃ iron (II) nitride Fe₃N₂ Carbon tetra fluoride CF₄ barium sulfite BaSO₃ Cobalt (II) Acetate Co(C₂H₃O₂)₂ dinitrogen tetraoxide N₂O₄ Hydrochloric Acid HCl(aq) silver sulfide Ag₂S Potassium permanganate KMnO₄ ammonia NH₃ tin (II) cyanide Sn(CN)₂ cesium nitrate CsNO₃ Manganese (II) Chlorate Mn(ClO₃)₂ nitrous acid HNO₂(aq) diphosphorus pentaoxide P₂O₅ Bonus 10 points: All work must be shown for credit. There are two parts to this problem, both must shown for credit. Chlorine has two stable isotopes, Cl-35 and Cl-37. If their exact masses are 34.9689 amu and 36.9695 amu, respectively, what is the natural abundance of Cl-35? (The atomic 1 mass of chlorine is 35.45, 2 a) Let x = fraction of Cl-35 y = fraction of Cl-37 x + y = 1 y = 1 - x 34.9689x + 36.9695y = 35.45 34.9689x + 36.9695(1 - x) = 35.45 Solving for x: x = 0.7595 y = 0.2405 Multiply by 100 to find % Ans: % Cl-35 = 75.95% % Cl-37 = 24.05%