The document discusses tips for solving chemistry problems on standardized tests. It provides an example problem calculating density and walks through the steps to solve it using the tips. The first tip is to eliminate the highest and lowest multiple choice options, leaving 0.079 and 0.79. The second tip is to make an educated guess between the two options based on knowledge of densities. It recognizes ethanol is less dense than water and selects 0.79 as the answer.

1. Chemistry Item #5 What is the density (g /mL) of a sample of ethyl alcohol if a 63.3 g sample occupies 80.0 mL? 0.079 0.79 1.26 12. www.upcatreview.com

2. Forgot the formula? www.upcatreview.com

3. It’s not a hopeless case... www.upcatreview.com

4. You could follow two of our tips: www.upcatreview.com

5. First, www.upcatreview.com

6. www.upcatreview.com #31 Remove Extremes For numerical items, remove the extremes ( highest and lowest choice) and choose from the middle values.

7. This tip should only be used when you have no idea on how to solve the problem. www.upcatreview.com

8. Chemistry Item #5 What is the density (g /mL) of a sample of ethyl alcohol if a 63.3 g sample occupies 80.0 mL? 0.079 0.79 1.26 12.6 www.upcatreview.com

9. You’re now left with two choices... www.upcatreview.com

10. Second tip: www.upcatreview.com

11. www.upcatreview.com #25 Educated Guess If you need to make a guess then it should be an educated guess . First, eliminate the answers that you know are wrong , then try your best to establish a basis for your choice.

12. With the two choices left, www.upcatreview.com

13. Chemistry Item #5 What is the density (g /mL) of a sample of ethyl alcohol if a 63.3 g sample occupies 80.0 mL? 0.079 0.79 1.26 12.6 www.upcatreview.com

14. If you have the knowledge... www.upcatreview.com

15. ...that water is more dense than most alcohols. www.upcatreview.com

16. Perhaps because alcohols evaporate faster than water? www.upcatreview.com

17. And if you also have the knowledge... www.upcatreview.com

18. ...that the density of water is 1 g/ml www.upcatreview.com

19. Then, choice C is also eliminated... www.upcatreview.com

20. ...simply because it’s higher than 1. www.upcatreview.com

21. Chemistry Item #5 What is the density (g /mL) of a sample of ethyl alcohol if a 63.3 g sample occupies 80.0 mL? 0.079 0.79 1.26 12.6 www.upcatreview.com

22. Thus, the answer is... www.upcatreview.com

23. B. 0.79 www.upcatreview.com

24. To verify, www.upcatreview.com

25. Density = mass ÷ volume Density = 63.3 ÷ 80.0 =0.79125 ≈ 0.79 www.upcatreview.com