Exam Week 1-1 - exam PDF

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Name____________________ Student ID Chem 1B – Exam 1

1. Consider the following set of linear data. Find the density of the liquid at 68°C using the graphical method you used in the lab activity. volume mass (you don’t need to upload your spreadsheet work (mL) (g) Just sketch a rough copy here) 0.0 140 18.8 157 28.9 168 42.0 181 62.0 202 79.1 219 90.0 229

2. Of the seven quantities of interest in Chemistry, which quantity is directly measured with a device that looks like this?

3. How many moles of water molecules are in this ice cube of pure water? The ice cube has dimensions 3 cm x 3cm x 3 cm (height, width, length) and weighs 24.7536 grams

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4. Imagine the ice-cube in Question #3 melts (H2O(s) and H2O(l) do not have the same volume), and therefore do not have the same density. If the density of the liquid water is 0.994 g/mL, how many individual water molecules are in the liquid water?

5. Consider the following conversion equation. Which of the 7 quantities of interest in chemistry are you solving for?

0.55 mol

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6. Consider the following conversion which is an example of a unit conversion. Which quantity of interest in chemistry is involved a. b. c. d. e.

metric volume to metric mass metric volume to metric volume volume to heat volume to pressure fluid ounces to mass ounces

85.3 mL

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7. Consider this sample of water which has a density = 0.996 g/mL and molar mass = 18.0 g/mol. The mass of the empty graduated cylinder = 142.126 grams Find all 3 quantities of Mass___________ Volume _________ Particle Count of molecules (moles)_________

8. How many moles of NaCl are found in 25.0 mL of a 0.5 M solution?

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9. If you have a 2-liter bottle of 1.8 M NaCl solution and you use a pipette to remove 10.0 mL of the solution, how many moles of NaCl did you remove from the 2-liter bottle?

10. If you place 0.85 grams of NaCl into an empty volumetric flask and fill the flask to the 250.00 mL mark with water, what is the concentration of the solution you just made in units of molarity?

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