SCIN131 Lesson 04 - Week 04 Quiz Questions with 100% Correct Answers

Lesson 04 - Week 04 Quiz Return to Assessment List Part 1 of 3 - 44.0/ 52.0 Points Question 1 of 25 4.0/ 4.0 Points `Eureka! I've discovered a new compound! Yay for me. I have determined that its empirical formula, but in order to determine its actual molecular formula, I need to know which of the following? • A. the number of moles of the compound in a 1.00 g sample of the substance • B. the density of the compound • C. the boiling point and freezing point of the compound • D. the molar mass of the compound. • E. none of these Feedback:Great! Empirical Formula discussed in Chapter 6.2. Question 2 of 25 4.0/ 4.0 Points Dihydrogen monoxide is the formula for a substance that makes up about 60% of the human body. What is mass percent of hydrogen in this compound? • A. 1.01% • B. 10.1% • C. 88.8% • D. 11.2% Feedback:Great! Mass percent discussed in Chapter 6.2. Question 3 of 25 4.0/ 4.0 Points `Before 1982, pennies were made of copper. From 1983 on, they are made of zinc, and only thinly plated with copper. The purity of those pre-1982 pennies are really about 95% copper (5% zinc and tin), but from they were actually pure copper. If you had a penny from 1820 that had a mass of 3.11 grams, how many atoms of copper would you have? • A. 1.97 • B. 6.02 × 1023 • C. 2.95 × 1022 • D. 8.13 × 10-26 • E. 1.19 × 1026 Feedback:Great! Mass percent discussed in Chapter 6.2. Question 4 of 25 4.0/ 4.0 Points `Nicotine (C10H14N2), a member of the nightshade family of plants, is an oily liquid that makes up between 0.6 to 3% of a cigarette's mass. Contact with the liquid pure form can cause death within hours, as nicotine passes through the dermis and heads directly for the bloodstream. Overdoses and death can easily occur in those smoking cigarettes with nicotine patches applied on their body. How many nicotine molecules are in 1.00 g of nicotine? • A. 3.71 x 1021 • B. 9.76 x 1025 • C. 1.02 x 10-26 • D. 2.32 x 1022 Feedback:Great! Mass percent discussed in Chapter 6.2. Question 5 of 25 4.0/ 4.0 Points The empirical formula of an organic molecule is CH; its molar mass is 104.1 g/mol. What is the molecular formula of the molecule? • A. C10H12 • B. C6H6 • C. None of these. • D. C2H4 • E. C8H8 Feedback:Great! Empirical Formula discussed in Chapter 6.2. Question 6 of 25 4.0/ 4.0 Points Salicyclic acid (C7H6O3) is commonly the active ingredient in face washes designed to help with acne. What is the mass percent of carbon in this compound? • A. 60.9% • B. 3.47% • C. 6.09% • D. 34.7% Feedback:Great! Mass percent discussed in Chapter 6.2. Question 7 of 25 4.0/ 4.0 Points `I was wading in the creek and discovered what I thought to be a small meteorite. I took it home and found its mass to be 12.00 kg. I ran some fancy schmancy chemical tests on it, and determined that the mass of nickel within the sample was 300.0 grams. What is the mass percent of nickel in the meteorite? • A. 25.00% • B. 4.000% • C. 2.500% • D. 100.0% Feedback:Great! Mass percent discussed in Chapter 6.2. Question 8 of 25 4.0/ 4.0 Points `A compound known as deuterium oxide, or "heavy water" is sometimes used in nuclear research. It is water, but each hydrogen atom in a "heavy water" molecule has a neutron in the nucleus in addition to the normal proton. So, what would be the percent hydrogen (by mass) in a "heavy water" molecule? • A. 20.1% • B. 79.9% • C. 11.2% • D. 88.8% Feedback:Great! Mass percent discussed in Chapter 6.2. Question 9 of 25 0.0/ 4.0 Points `I was wading in the creek and discovered what I thought to be a small meteorite. I took it home and found its mass to be 5.50 kg. I ran some fancy schmancy chemical tests on it, and determined that the mass of nickel within the sample was 250.0 grams. What is the mass percent of nickel in the meteorite? • A. 0.5454% • B. 0.4545% • C. 4.545% • D. 45.45% Feedback:Mass percent discussed in Chapter 6.2. Question 10 of 25 4.0/ 4.0 Points A sample of pure lithium carbonate contains 18.8% lithium by mass. What is the % lithium by mass in a sample of pure lithium carbonate that has twice the mass of the first sample? • A. 75.2% • B. 37.6% • C. 18.8% • D. 9.40% Feedback:Great! Mass percent discussed in Chapter 6.2. Question 11 of 25 4.0/ 4.0 Points `One of the first chemical WMDs, researchers initially produced VX nerve agent for retail sale in the 1950s as a pesticide. Thankfully, your likelihood of coming in contact with VX is extremely low - the world's stockpiles have been destroyed, including the United States' main stockpile in Anniston, AL. The molecular formula for this nerve agent is C11H26NO2PS, and it has a molar mass of 267.37 g/mol. Given this information, what is its empirical formula? • A. CH2.36N0.09O0.18P0.09S0.09 • B. C11H26NO2PS • C. C22H52N2O4P2S2 • D. C66H156N6O12P6S6 • E. none of these are the correct empirical formula Feedback:Great! Empirical Formula discussed in Chapter 6.2. Question 12 of 25 4.0/ 4.0 Points The empirical formula of an insecticide is found to be CHCl, and its molar mass is 290.8 g/mol. How many atoms of carbon are found in a molecule of the insecticide? • A. 6 • B. 4 • C. 3 • D. 2 • E. 8 Feedback:Great! Empirical Formula discussed in Chapter 6.2. Question 13 of 25 0.0/ 4.0 Points A vitamin contains the elements C, H, and O. It is known to contain 40.9% C and 4.58% H by mass. The molar mass of the vitamin has been found to be about 180 g/mol. The molecular formula for the vitamin is: • A. C4H6O4 • B. C6H8O6 • C. C14H18 • D. C2H3O2 • E. C3H4O3 Feedback:Empirical Formula discussed in Chapter 6.2. Part 2 of 3 - Part 02 28.0/ 40.0 Points Question 14 of 25 0.0/ 4.0 Points `Caves form mostly from the reaction of weak carbonic acid (which forms due to carbon dioxide that is in the water) with exposed limestone. What numbers go in the blanks below, in order from left to right, to balance this chemical equation? H2CO3(aq) + CaCO3(s) --> Ca(HCO3)2(aq) + CO2(g) + H2O(l) • A. 2, 1, 1, 3, 1 • B. 2, 3, 6, 4, 2 • C. 2, 3, 1, 2, 1 • D. 3, 1, 1, 2, 2 • E. none of the above Feedback:Topic discussed in section 7.1-7.2. Question 15 of 25 4.0/ 4.0 Points Which of the following compounds is soluble? • A. copper carbonate • B. calcium carbonate • C. strontium carbonate • D. sodium carbonate Feedback:Great! Topic discussed in section 7.1-7.2. Use solubility table. Question 16 of 25 4.0/ 4.0 Points `Generally, for a decomp reaction to take place, what else must be added to the reaction? • A. light • B. heat • C. electrical current • D. energy • E. any of the above Feedback:Great! Topic discussed in section 7.1-7.2. Question 17 of 25 0.0/ 4.0 Points `When you are balancing the reaction NO2 + H2O + O2 → HNO3 , what number goes in front of O2? • A. 5 • B. 2 • C. 3 • D. 4 • E. 1 Feedback:Topic discussed in section 7.1-7.2. Question 18 of 25 4.0/ 4.0 Points I have the following items in my kitchen. Which one is NOT an acid? • A. can of Coke • B. lemon juice • C. vinegar • D. baking soda Feedback:Great! Topic discussed in section 7.1-7.2. Question 19 of 25 4.0/ 4.0 Points `Sometimes we see abbreviations for the physical states of chemicals written as subscripts in chemical reactions--(aq), (s), (l), (g). If you are writing the equation for a reaction in which a precipitate forms, how many of these abbreviations will ALWAYS appear in the equation? • A. 1 • B. 2 • C. 3 • D. 4 • E. none are required to always appear Feedback:Great! Topic discussed in section 7.1-7.2. Question 20 of 25 0.0/ 4.0 Points The reaction below is shown for diesel fuel reacting in a vehicle. What type of reaction is this? 4 C12H23 +71 O2 –> 48 CO2 + 46 H2O • A. redox • B. precipitation • C. acid-base • D. double displacement • E. combustion Feedback:Topic discussed in section 7.1-7.2. Question 21 of 25 4.0/ 4.0 Points `You are given an unknown chemical that is dissolved in water. Your task is to identify it. From the beginning, you know your unknown chemical cannot be which of the following? • A. calcium sulfate • B. ammonium chloride • C. potassium carbonate • D. barium sulfide • E. sodium phosphate Feedback:Great! Topic discussed in section 7.1-7.2. Use solubility table. Question 22 of 25 4.0/ 4.0 Points `I was digging around in the kitchen and came across the following items. Which one is most likely not an acid? • A. lime • B. orange • C. dishsoap • D. vinegar • E. none of these are acids Feedback:Great! Topic discussed in section 7.1-7.2. Question 23 of 25 4.0/ 4.0 Points What numbers, in the correct order from left to right, would go in the blanks in order to balance this equation: Ca3(PO4)2 + H2SO4 → CaSO4(aq) + Ca(H2PO4)2(aq) • A. 1,2,2,1 • B. 1,2,1,2 • C. 2,1,1,2 • D. 2,2,2,2 Feedback:Great! Topic discussed in section 7.1-7.2. Part 3 of 3 - Part 03 4.0/ 8.0 Points Question 24 of 25 4.0/ 4.0 Points `If you weighed out a small sample of lithium acetate, then dumped it into a beaker of water and stirred it around, which of these statements would NOT be true? • A. The the lithium acetate will fail to dissociate • B. The solution will taste salty. • C. The solution will conduct electricity. • D. Individual lithium and acetate ions are present. • E. none of the above Feedback:Great! Electrolytes are discussed in 11.2 Question 25 of 25 0.0/ 4.0 Points 'We discussed how some solutions are electrolytes in this lesson. Which of these would be a strong one? • A. HCl • B. NH4Cl • C. NaC2H3O2 • D. NaCl • E. all of the above Feedback:Electrolytes are discussed in 11.2