Chemistry Final Study Guide PDF

# Chemistry Final Study Guide ## 1. How many significant digits are there in each of the following? - 146.32 cm: 5 - 700 m: 1 - 700. m: 3 - 700.5 m: 4 ## 2. Round off each of the following to two significant figures: - 5.934: 6.9 - 0.00683: 0.0068 - 7,690,000: 7,700,000 ## 3. Calculate the dens...

# Chemistry Final Study Guide ## 1. How many significant digits are there in each of the following? - 146.32 cm: 5 - 700 m: 1 - 700. m: 3 - 700.5 m: 4 ## 2. Round off each of the following to two significant figures: - 5.934: 6.9 - 0.00683: 0.0068 - 7,690,000: 7,700,000 ## 3. Calculate the density of each of the following sets of data. Express each answer in correct significant figures. | Volume (mL) | Mass (g) | Density (g/mL) | |---|---|---| | 4.3 | 40 | 9.3 | | 15.3 | 3.0 | 0.20 | | 9.22 | 3.11 | 0.337 | | 2.4 | 23 | 9.6 | **Explanation:** * An original volume is 13.5 mL and is raised to 15.9 mL when the object is added. The mass of the object is 23 g. * Therefore, the volume of the object is 15.9 mL - 13.5 mL = 2.4 mL * The density of the object is 23 g / 2.4 mL = 9.6 g/mL ## 4. Complete the following conversions. DECIMAL SHIFT WILL NOT BE ACCEPTED! | Conversion | Answer | |---|---| | 125 mL = | 125,000 µL | | 1000 g = | 100 dag | | 1,000,000 µm = | 1 m | | 1000 µL = | 1 mL | | 1000 mm = | 1 m | ## 5. What is the density of Object G with volume 9 mL? - 6 g / 9 mL = 0.666 g/mL ## 6. What is the density of Object E with mass 7 g? - 7 g / 3 mL = 2.33 g/mL ## 7. Would Object E with mass of 7 g float or sink in water with the same mass? - Sink ## 8. How are ionic compounds formed (what happens with their electrons)? - **Transferred electrons** **a. What kinds of elements/particles form them?** - Metal + non-metal **b. What kinds of elements form cations? Give an example.** - Metals (Na+) **c. What kinds of elements form anions? Give an example.** - Non-metals (Cl-) **d. Electronegativity difference range?** - Large difference **e. Do they tend to form electrolytes in solution? Give an example.** - Yes, ions are electrolytes (Mg+2) ## 9. How are covalent compounds (molecules) formed (what happens with their electrons)? - **Sharing electrons** ## 10. Do they commonly form electrolytes in solution? Give an example. - No, electrolytes because no ions formed. ## 11. Describe each of the two kinds of COVALENT bonds (molecules): **a. Polar covalent bonds** - **i. Electronegativity difference:** Some difference - **ii. Examples:** PF3, H2O **b. Non-polar covalent bonds** - **i. Electronegativity difference:** No difference - **ii. Examples:** CH4 **c. How many electrons are shared in a:** | Bond | Number of electrons shared | |---|---| | Single bond | 2 | | Double bond | 4 | | Triple bond | 6 | ## 12. How does energy play a part in the breaking or forming of bonds? - Energy released forms bonds, energy gained breaks bonds. ## 13. Draw the electron dot diagram of the following: **a. An atom that has 2 valence electrons** - Mg: ``` * Mg * ``` **b. An atom that has 4 valence electrons** - C: ``` * * C * * ``` ## 14. Describe what happens when each of the following changes on a neutral atom **a. Protons change:** Positive **b. Neutrons change:** Neutral **c. Electrons increase:** Negative (gaining) **d. Electrons decrease:** Positive (losing) ## 15. How do you calculate the mass of an isotope? - Multiply each mass by their abundance and add together. ## 16. Complete the table: | COVALENT Formula | COVALENT Name | |---|---| | C3O | Tricarbon monoxide | | N5Cl4 | Pentanitrogen tetrachloride | | I6H2 | Hexaiodine dihydride | | S9Se8 | Nonasulfur octaselenide | | ArI4 | Arsenic tetriodide | | Si2Br7 | Disilicon heptabromide | ## 17. Describe heterogeneous mixture. Give an example. - You can see the different parts (sand) ## 18. Describe homogeneous mixture. Give an example. - Looks the same/uniform (salt water) ## 19. Describe a pure substance. **a. Give an example of an element.** - Iron **b. Give an example of a compound.** - Sodium chloride ## 20. What are the 6 indicators of a chemical change? - Production of gas, heat, color, precipitate, odor, light ## 21. Give examples of physical vs chemical changes. | Physical Changes | Chemical Changes | |---|---| | Cutting, dissolving, melting | Burning, oxidizing | ## 22. A substance can conduct if: - It has ions in solution or a metal. ## 23. What kinds of compounds will disperse? Give examples and show how they disperse. - **Covalent:** ``` H₂O * O * O * * ``` ## 24. What kinds of compounds will dissociate? Give examples and show how they dissociate. - **Ionic:** ``` H₂O + C - + H₂O + Na - + Na - ``` ## 25. Define solubility. - The ability/amount of solute that can dissolve. ## 26. Finish the sentences with the term INCREASES or DECREASES **a. Most solids become more soluble in water when the temperature **increases**. **b. Most gases become more soluble in water when the temperature **decreases**. **c. Most gases become more soluble in water when the pressure **increases**. ## 27. If a substance does not dissolve in water, has low conductivity and low melting point, this substance would most likely be: Circle the correct answer(s). a. Polar covalent molecule **b. Nonpolar covalent molecule** c. Ionic ## 28. If a substance forms a solution with water, it would most likely be: Circle the correct answer(s). a. Polar covalent molecule b. Nonpolar covalent molecule **c. Ionic**