Identify each of the following as a physical or chemical change. 21. __ You leave your bicycle out in the rain and it rusts. 22. __ A sugar cube dissolves. 23. __ Scientist break-up water into oxygen and hydrogen gas. 24. __ Burning coal for a barbecue. 25. __ Trimming a bush because it has grown too tall.

How many Sodium ions are in 156 moles of Sodium ions? $9.39\times 10^{23}$ Sodium ions $2.59\times 10^{-24}$ Sodium ions $6.022\times 10^{23}$ Sodium ions 1.56 Sodium ions

Which of the following alcohols will be used in this lab? Butanol Propanol Ethanol Methanol

Acidic dyes work best in low pH environments. are used for staining negatively charged molecular structures. are negatively charged and work best at low pH. are lipid soluble. are negatively charged.

How many protons does carbon have? 40 39.09 6 12

Measurements taken with a spectrometer require a __ to eliminate background readings from components other than what is being measured in the sample. Select one: a. sample b. replicate c. treatment d. blank

11. [Periodic Table and Periodic Law] Which of the following elements has the greatest tendency to attract electrons in a chemical bond? A. Carbon B. Oxygen C. Fluorine D. Nitrogen

Name the following organic compounds: compound name $\square $ $CH_{2}-CH_{2}-CH_{3}\\ \downarrow \\ CH_{3}-CH_{2}-C-CH_{2}-CH_{2}-CH_{3}\\ CH_{3}-CH_{2}-CH_{2}$ $\square $ $CH_{3}-CH_{2}-CH_{2}\\ CH_{3}-CH_{2}-CH_{2}-C-CH_{2}-CH_{2}-CH_{3}\\ \downarrow \\ CH_{2}-CH_{3}$ $\square $ $\square $ $CH_{3}\\ \downarrow \\ CH_{3}-CH_{2}-CH_{2}-CH_{3}\\ CH_{3}-CH_{3}$ $\square $ $\square $

-Develop possible solutions - Brainstorming - think of as many solutions as possible of \( \mathrm{CO}_{2} \) wooden car

8. Every chlorine atom has: 7 electrons 17 neutrons a mass number of 35 an atomic number of 17

1. $6P_{4}O_{10}+H_{2}O$ $3H_{3}PO_{4}$