CHM142 Questions And Answers Latest Top Score.

CHM142 Questions And Answers Latest Top Score. Fog Lemonade with Pulp Salt water A cup of hot tea - correct answer. There are three types of mixtures that involve a solute dissolving into a solvent: solutions, colloids, and suspensions. The size of the solute, or the particle being dissolved, determines whether the resulting mixture is a solution, colloid, or suspension. Which of the following is an example of a colloid? 20 g 5 g 10 g 30 g - correct answer. The solubility of solids is affected by temperature while the solubility of gases is affected by both temperature and pressure. The Solubility of Solids The solubility of a solid solute increases with increasing temperature because the thermal energy helps to overcome the attractions between solute molecules in the solid. The Solubility of Gases The solubility of a gaseous solute decreases with increasing temperature because the thermal energy helps to overcome the attractions between solute and solvent molecules. The solubility of a gaseous solute increases as pressure of the solute gas above the solution is increased because a higher pressure means that more gas molecules are present near the surface of the solution and able to dissolve. How much KNO3 can dissolve in 50 g of water at 10 °C? CH3OH (methanol, polar) BF3 (Boron trifluoride, nonpolar) CCl4 (carbon tetrachloride, nonpolar) C4H10 (butane, nonpolar) - correct answer. There must be a strong attraction between the solute and the solvent molecules in order for the solute to dissolve in the solvent allowing a solution to form. Which substance will dissolve in water, a polar substance? 8.84 g glucose/108.84 g solution 8.84 g glucose/91.16 g solution 8.84 g glucose/100 g solution 8.84 g glucose/100 g water - correct answer. Which expression is equivalent to 8.84% (m/m) glucose? 3.6 °C -3.6 °C 10.1 °C -10.1 °C - correct answer. Colligative properties of solutions depend only on the number of particles dissolved in a solvent. The higher the number of dissolved solute particles, the larger the effect on the boiling point, melting point, vapor pressure, and osmotic pressure. What is the freezing point of 0.500 m I2 in cyclohexane (normal freezing point = 6.55 °C)? Kf,cyclohexane = 20.2 °C/m 0.690 0.310 0.136 0.157 - correct answer. While not used as frequently, mole fraction is another unit of concentration. Mole fraction is the fraction of moles of one substance over the total moles in the sample. mole fraction(x) = molesA/total moles What is the mole fraction of Ar in a sample with 12.4 grams Ar, 35.0 g N2, and 2.91 g He? Water (solvent) will move into the first compartment Water (solvent) will move into the second compartment Both water (solvent) and starch (solute) will move into the first compartment. Starch (solute) will move into the second compartment. - correct answer. Osmosis is the spontaneous movement of solvent molecules across a semi-permeable membrane from an area of lower solute concentration to an area of higher solute concentration. This membrane freely allows smaller solvent molecules to pass through, but it does not allow the larger solute molecules to pass through. The solvent will diffuse across the membrane as it travels from area with the lower solute concentration to the area with the higher solute concentration. The process will continue until the concentration of solute on both sides of the semi-permeable membrane is equal. Assume there is a semipermeable membrane separating two compartments: the first compartment contains 8% starch, and the second compartment is 3% starch. Select the answer that indicates what molecules will move and the correct direction. A homogeneous mixture of two or more substances A mixture in which a dispersed substance is finely divided but not truly dissolved in a dissolving medium A heterogeneous mixture in which solute particles settle out of solution - correct answer. Which description is best for a solution? 2.18 atm 2.44 atm 16.6 atm 21.5 atm - correct answer. Colligative properties of solutions depend only on the number of particles dissolved in a solvent. The higher the number of dissolved solute particles, the larger the effect on the boiling point, melting point, vapor pressure, and osmotic pressure.