Part -1:
1. Classify each of the following as a homogeneous mixture, heterogeneous mixture, element, or compound:
(a) table salt, (b) blood, (c) steel, (d) planet Earth.
2. If nitrogen, N2, were pumped into your lungs at high pressure, what would happen to its solubility in your blood?
2. Why is rain or snow called precipitation?
3. Cells at the top of a tree have a higher concentration of sugars than cells at the bottom. How might this fact assist a tree in moving water upward from its roots? Readiness Assurance Test
4. Half-frozen fruit punch is always sweeter than the same fruit punch completely melted because
(a) the sugar sinks to the bottom.
(b) only the water freezes while the sugar remains in solution.
(c) the half-frozen fruit punch is warmer.
(d) sugar molecules solidify as crystals.
5. Why does the fluorine atom tend to gain only one electron?
6. What is the primary difference between a chemical bond and an attraction between two molecules?
Part -2
1. Which is stronger: the covalent bond that holds atoms together within a molecule or the electrical attraction between two neighboring molecules? Explain.
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2. An atom loses an electron to another atom. Is this an example of a physical or chemical change?
(a) chemical change involving the formation of ions
(b) physical change involving the formation of ions
(c) chemical change involving the formation of covalent bonds
(d) physical change involving the formation of covalent Bonds
2. Aluminum ions carry a 3+ charge, and chloride ions carry a 1- charge. What is the chemical formula for the ionic compound aluminum chloride?
(a) Al3Cl
(b) AlCl3
(c) Al3Cl3
(d) AlCl
3. How is a solution different from a suspension?
4. Why does the solubility of a gas solute in a liquid solvent decrease with increasing temperature?
Exercises
5. Mixtures can be separated into their components by taking advantage of differences in the chemical properties of the components. Why might this separation method be less convenient than taking advantage of differences in the physical properties of the components?
6. Many dry cereals are fortified with iron, which is added to the cereal in the form of small iron particles. How might these particles be separated from the cereal?
7. Classify each of the following as a homogeneous mixture, heterogeneous mixture, element, or compound:
(a) table salt, (b) blood, (c) steel, (d) planet Earth.
8. Which of the boxes above best represents a suspension?
9. Which of the boxes above best represents a compound?
10. What generally happens to the rate of a chemical reaction with increasing temperature?
Exercises
11. Balance these equations:
(a) ____Fe(s) + ____O2(g)h____ Fe2O3(s)
(b) ____H2(g) + ____N2(g)h____NH3(g)
(c) ____Cl2(g) + ____KBr(aq)h____Br2(l ) +____KCl (aq)
(d) ____CH4(g) + ____O2(g)h____CO2(g) +____H2O(l )
12. Which of these two chemical equations is balanced?
2 C4H10( g) + 13 O2( g)h8 CO2( g) + 10 H2O(l )
4 C6H7N5O16(s) + 19 O2( g)h24 CO2( g)+ 20 NO2( g) + 14 H2O(g)
Discussion Questions
13. Many people hear about atmospheric ozone depletion and wonder why we don't simply replace the ozone that has been destroyed. Knowing about chlorofluorocarbons and knowing how catalysts work, explain how this would not be a lasting solutions.
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14. The yeast in bread dough feeds on sugar to produce carbon dioxide. Why does the dough rise faster in a warmer area?
(a) There is a greater number of effective collisions among reacting molecules.
(b) Atmospheric pressure decreases with increasing temperature.
(c) The yeast tends to "wake up" with warmer temperatures, which is why baker's yeast is best stored in the refrigerator.
(d) The rate of evaporation increases with increasing temperature.