Chapter 1, Problem 1.91AE

Beakers (a), (b), and (c) are representations of tiny sections (not to scale) of mixtures made from pure benzene and pure water. Select which beaker gives proper representation of the result when the two pure substances are mixed.

You receive a mixture of table salt and sand and have to separate the mixture into pure substances. Explain how you would carry out this task. Is your method based on physical or chemical properties? Explain.

The label on a bale of mulch indicates a volume of 1.45 ft3. The label also states that the mulch in the bale will cover an area of a garden 6 ft 6 ft to a depth of 1 in. Account for the discrepancy in the given volumes.

Aspirin is a pure substance. If you had the choice of buying a widely advertised brand of aspirin whose effectiveness is well known or the generic product of a new manufacturer at half the price, which would you buy? Explain.

You can analyze for a copper compound in water using an instrument called a spectrophotometer. [A spectrophotometer is a scientific instrument that measures the amount of light (of a given wavelength) that is absorbed by the solution] The amount of light absorbed at a given wavelength of light (A) depends directly on the mass of compound per liter of solution. To calibrate the spectrophotometer, you collect the following data: Plot the absorbance (A) against the mass of copper compound per liter (g/L), and find the slope (m) and intercept (b) (assuming that A is y and the amount in solution is x in the equation for a straight line, y = mx + b). What is the mass of copper compound in the solution in g/L and mg/mL when the absorbance is 0.635?

All of the following processes involve a separation of either a mixture into substances or a compound into elements. For each, decide whether a physical process or a chemical reaction is required. a Sodium metal is obtained from the substance sodium chloride. b Iron filings are separated from sand by using a magnet. c Sugar crystals are separated from a sugar syrup by evaporation of water. d Fine crystals of silver chloride are separated from a suspension of the crystals in water. e Copper is produced when zinc metal is placed in a solution of copper(II) sulfate, a compound.

In my on-campus Organic Chemistry II Lab, my students make aspirin. The melting point in the literature for aspirin is 134-136°C.   Suppose the sample of aspirin one of my students made has a melting point range of 129-133 °C.  Using this information, answer the following: 1.  Do you think the student made aspirin?  Why or why not? 2.  How could you test your hypothesis?  Explain what you would do and what the results would look like if they made aspirin versus if they didn't.

. A sample of an ethanol-water solution has a volume of 52.5 cm³ and a mass of 49.6 g. What is the percentage of ethanol (by mass) in the solution? (Assume that there is no change in volume when the pure compounds are mixed.) The density of ethanol is 0.789 g/cm³ and that of water is 0.998 g/cm³. Percentage of ethanol = b. Alcoholic beverages are rated in proof, which is a measure of the relative amount of ethanol in the beverage. Pure ethanol is exactly 200 proof, a solution that is 50% ethanol by volume is exactly 100 proof. What is the proof of the given ethanol-water solution? proof Submit Answer % [References] Try Another Version 10 item attempts remaining

A scientist performs an experiment to determine the density of a sugar solution.  He obtains the following results:  1. 09 g/mL, 1. 81 g/mL, 1. 93 g/mL, and 1. 73 g/mL.  If the actual value for the density of the sugar solution is 1.75 g/mL, which statement below best describes her results? Her results are not accurate, but precise. Her results are both accurate and precise. Her results are neither accurate nor precise. It isn't possible to determine with the information given. Her results are not precise, but accurate.