We Wish to Lower the Freezing Point of the Water

question 70

Multiple Choice

We wish to lower the freezing point of the water in an automobile radiator to -40°C. The total mass of water present is 12.0 kg. For which one of the following compounds would we have to use the greatest mass of solute to achieve this? You may assume that Kf for water = -1.86°C/m and that all ionizable solutes are completely ionized with unit activity even at this high concentration.

• A) AlF3 (M.W. = 84 g/mol)
• B) C₂H₅OH (M.W. = 46 g/mol)
• C) CaCl₂ (M.W. = 111 g/mol)
• D) C₃H₆(OH)₂ (M.W. = 76 g/mol)
• E) NaCl (M.W. = 58.5 g/mol)

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Definitions:

Outcome Variable

The variable that is the result of an experiment or study, often measured to assess the effect of a treatment.

Two-Way ANOVA

A statistical test used to determine the effect of two nominal predictor variables on a continuous outcome variable, testing for interaction and main effects.

Factorial ANOVA

A statistical test used to determine the effect of two or more independent variables on a dependent variable at the same time, often used to analyze the interaction between factors.

F Statistic

A ratio used in ANOVA tests, comparing the variance between group means to the variance within groups to determine whether group means are significantly different from each other.