An analytical chemist measures the amount of Elements Ę₁ and E2 in four samples of an unknown Substance X: mass mass sample of E of E2 1 1 5.2 g 17.8 g It's known that X contains no elements other than Ę₁ and E2. 2 5.4 g 18.6 g 3 3.4 g 11.7 g 4 5.9 g 20.0 g Using this information, answer the questions in the table below. Is X a pure substance or a mixture? If you don't have enough information to decide, choose can't decide. If you said X is a pure substance, calculate the mass of Element Ę the analytical chemist would find in a new 10.0 g sample of X. Round your answer to 2 significant digits. pure substance mixture (can't decide) ☐ g x10 ☑

A compound associated with the odor of garlic on a persons breath has the chemical formula CyH8S and a formula mass of 88.19 amu. What number does y stand for in the chemical formula of the compound?

Which of the following compounds has the highest mass percent of chlorine? (a) BCl3 (b) AsCl3 (c) GaCl3 (d) AlCl3 (e) PCl3

Arrange the following substances in order of increasing mass percent of carbon. a. caffeine. C8H10N4O2 b. sucrose, C12H22O11 c. ethanol, C2H5OH

Two general chemistry students working together in the lab weigh out 0.832 g of CaCl2 2 H2O into a crucible. After heating the sample for a short time and allowing the crucible to cool, the students determine that the sample has a mass of 0.739 g. They then do a quick calculation. On the basis of this calculation, what should they do next? (a) Congratulate themselves on a job well done. (b) Assume the bottle of CaCl2 2 H2O was mislabeled; it actually contained something different. (c) Heat the crucible again, and then reweigh it.

A substance X2Z has the composition (by mass) of 40.0% X and 60.0% Z. What is the composition (by mass) of the compound XZ2?

A sample of an iron alloy contains 92.1 g Fe. 2.59 g C. and Cr. Calculate the percent by mass of each component present in the alloy sample.

In an experiment, you need 0.125 mol of sodium metal. Sodium can be cut easily with a knife (Figure 2.5), so if you cut out a block of sodium, what should the volume of the block be in cubic centimeters? If you cut a perfect cube, what is the length of the edge of the cube? (The density of sodium is 0.97 g/cm3.)

Atomic masses are relative masses. What does this mean?

There are five hydrocarbon compounds (compounds of C and II) that have the formula C6H14. (These are isomers; they differ in the way that C and H atoms are attached. Chapter 23) All are liquids at room temperature but have slightly different densities. (a) You have a pure sample of one of these hydrocarbons, and to identify it you decide to measure its density. You determine that a 5.0-mL sample (measured in a graduated cylinder) has a mass of 3.2745 g (measured on an analytical balance). Assume that the accuracy of the values for mass and volume is plus or minus one ( 1) in the last significant figure. What is the density of the liquid? (b) Can you identify the unknown hydrocarbon based on your experiment? (c) Can you eliminate any of the five possibilities based on the data? If so, which one(s)? (d) You need a more accurate volume measurement to solve this problem, and you redetermine the volume to be 4.93 mL Based on this new informationwhat is the unknown compound?