Question

1. How much heat energy, in joules, is required to raise the temperature of 25.00 g of ice cube at 0.00 C to 50.00°C? a. 25.35 kJ b. 1330.0 J c. 1555.0J d. 13.57 kJ e. 12.32 kJ 2. Estimate the vapor pressure of water at 65°C. (Hint: You know the vapor pressure at the boiling point of water.) a. 320 mmHg b. 195 mmHg c. 115 mmHg d. 550 mmHg e. 439 mmHg 3. Which of the following substances can be liquefied by applying pressure at 65°C? Substance critical temperature critical pressure SO 158 C 78 atm b. CH -82 C 46 atm CO -140C 35 atm d. 0 -119°C 50 atm CO 31°C 73 atm a. c. e. a. 4. An organic compound contains 26.7% of carbon, 2.2% of hydrogen and the remaining is oxygen. Determine its empirical formula. a. CHO b. CHO c. C,H,O, d. CHỊ0, e. CHO

Answer 1

mass u weight of substance = 25.00 initial temperature = oo final 50°c Specific heat of wate sa 4. 186 5/gie ice melting water water oc o'c , we need heat of fusion Q1 = (334 5/9 25.00) = 83505 Then we have to rise the temperature from oo to 50° heat must be supplied 50°c For melting m s 4T 25.00* 4.186 s/goe.* (so'ro') °c 5232.5 J Total heat must be supplied - (5 232.5+ 8380) 556653 2 1358 2.5 J 13.58 kJ Correct answer is option @

Again, Ја од 1-44)--)) 760 760 P = 6580 tour = 658 mm At T = 100°C - 373k; At T2 = 650 = 338 u ; P2= ? komola = 90.66 *10°s/moi. a Hvap = 90.66 KS R = 8.314 5/mor 760 40.66 is 8.3 14 373 P 2 338 40.66 x 108/ 2.68 & 103_2.958 x 103 8.319 760 2 1.3595 760 3.89 P2 ortpaf- 468189 | P2 = 195.51 Correct answer is 6. A Gas cannot be lianefied above the critical temperature, no matter how much pressure is applied, So only sor can be lianified above aroc because it has exitical temperatue 158 °C. So only it can be lianited.

(1 26.7%. Co 2.2%. #1 1100 100 - (26.4 +2.2 2012 71.1% 26.7 g c 26.07 12 2.2 % H 2.2. 11 1 molc 2.225 mol 2.2 2.2 mol 2.2 44375 mol 2.2 711 o do 71.1 16 emperical formula CH,02 CHOR

Molecular mass mass of CHOL 45g 45 2 CHO 2 100 lao H1 0 100 45 2x100 45 45 2.2 so the correct option formella H 0 2.2 4.4 C₂H₂O which has CH02 some emperical
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