Test 5 CHM1045C Fa06 - pink - answers

Test 5 CHM1045C Fa06 - pink - answers - Name. Recitation...

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Name……………………………………………………………… Recitation Section………………. Test 5 CHM1045C Monday December 4 th 2006 All questions carry the same marks. Do the easiest ones first. Here are some formulas and constants. No of moles = mass(g)/formula mass : Molarity = No of moles of solute/No of liters of solution PV = nRT : R = 8.3J/K.mol : at 273K 1mol of gas occupies 22.4L : N A =6 x 10 23 particles/mol Speed of light, c = 3 x 10 8 m/s : c = νλ Heat energy = mass(g) x specific heat capacity x temperature change(K) 1 Sugar dissolves in water. Is this a physical or chemical change? Physical 2 The SI unit of length is the metre. How many micrometres make 1m? 1 million 3 Water’s boiling temperature is 212 o F, 100 o C. What is its value in kelvins? 100 + 273 = 373 4 BaCO 3 has a mass fraction of Ba of 0.69. How much Ba is there in 30g of BaCO 3 ? 0.69 x 30 = 20.7 5 60 27 Co is the symbol for one isotope of cobalt. How many electrons, protons and neutrons (separately) are there in one atom of Co? At No 27, so 27protons, 27 electrons, (60 – 27) = 33 neutrons 6 What are the names of Zn(NO 3 ) 2 Zinc nitrate CuS Copper sulfide 7 What are the formulas of sodium sulfate Na 2 SO 4 calcium bromide? CaBr 2 8 The empirical formula of propene is CH 2 . Its molar (formula) mass ( M ) is 42. What is its molecular formula? (C = 12, H = 1)
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CH 2 has mass 12 + 2 =14: 42/14 = 3: so molecular formula = 3 x empirical formula = C 3 H 8 9 How many moles of calcium iodide (CaI
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Test 5 CHM1045C Fa06 - pink - answers - Name. Recitation...

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