chemistry+review+questions

=Questions ﻿= = you can use the link below for a periodic table to help you answer the chemistry questions : = =﻿=

1. Who created the Periodic Table and how is it organized?
 * Dimitri Mendeleev created the Periodic Table. It was originally organized by the atomic mass. Now it is organized by the atomic number. or charles darwin **

2. How is an element different than a compound? give examples.


 * elements make up compounds, as atoms make up molecules. A compound is a a combination of two or more elements **

Example, Compound: Water elements: hydrogen (two atoms), oxygen (one atom) covalent bond Compound: Salt elements: Na (sodium) on atom and Cl (chlorine) one atom ionic bond Compound: Calcium Chloride elements: Ca (one atom) Cl (two atoms) ionic bond Compound: Carbon Dioxide elements : carbon (one atom) and oxygen (two atoms) covalent bond

3. What are the two most abundant elements on the Earth's crust?
 * Sillicon and Oxygen **

4. What are the two most abundant elements in the human body?
 * Carbon and Oxygen **

5. Helium, Neon, Argon, Krypton, Xenon, and Radon belong to what **Group** on the periodic table? (He, Ne, Ar, Kr, Xe, and Rn) Noble Gases

6. Do Hydrogen, lithium, Sodium, and Potassium (H, Li, Na, K) belong to a ** Group ** or **Period** ? (H, Li, Na, K) Explain. **Period**

7. Boron, Carbon, Nitrogen, Oxygen, Flourine (B, C, N, O, F) belong to a **Group** or **Period** ? Explain. **Group**

8. Using the Periodic Table, fill in the table below for the element CARBON. (C) = =

Draw or insert a picture of a Carbon Atom below:
 * ** t he atomic # ** || ** 6 ** ||
 * ** the atomic mass ** || ** 12 ** ||
 * ** number of protons ** || ** 6 ** ||
 * ** number of neutrons ** || ** 6 ** ||
 * ** number of electrons ** || ** 6 ** ||
 * ** valence electrons ** || ** 4 ** ||



9. Using the Periodic Table, fill in the table below for the element CHLORINE. (Cl)


 * the atomic # || 17 ||
 * the atomic mass || 35 ||
 * number of protons || 17 ||
 * number of neutrons || 18 ||
 * number of electrons || 17 ||
 * valence electrons || 7 ||

Draw a picture or insert a picture of a Chlorine atom below:



The diagram above has 7/8 electrons in the outer shell. the valence electron number is 7.

10. Would an atom (like Chlorine) with a different number of electrons (+1 charge) be considered an Ion or an Isotope?


 * The positively charged Chlorine atom would be an Ion - which is an atom with a different number of electrons. **


 * Chlorine has 17 protons or + 17 **
 * Chlorine has 17 electrons or -17 **


 * If you add an electron, the atom will become a negatively charged ion **
 * If you loose and electron, the atom will become a postively charged ion **

11. Would an atom (like Carbon) with a different atomic mass and different number of neutrons be considered an Ion or Isotope? This would be an isotope. If you change the number of neutrons, the atomic mass changes. The charge remains the same (same number of electrons). The atomic number stays the same (same number of neutrons)

12. How is a mixture different than a compound? Use both water and mud as your examples.


 * A mixture such as dirt and water can be taken apart by a filter or a screen. A mixture is not bonded together and can be separated easily **


 * A compound is it's own thing that can't be taken apart very easily because instead of a two mixed compounds it's it's own element and therefore it's own compound too. An example would be water or salt. These two compounds have strong bonds between their elements and are difficult to separate. **

13. Why would a snowglobe be considered a suspension and not a solution?
 * Since the large particles can be seen floating in solution, they have not fully dissolved in the water. It would be easy to separate the mixture using a screen or a filter. **

14. Why would a salt mixed in water be considered a solution and not a suspension?


 * Because it is identical through out. It would be more difficult to seperate. You could seperate by boiling or using an evaporating dish. You can't separate using a filter or a screen. **

15. Give ten different examples of a physical change.

some examples: 1) Aluminum foil is cut in half. 2) Clay is molded into a new shape. 3) Butter melts on warm toast. 4) Water evaporates from the surface of the ocean. 5) A juice box in the freezer freezes. 6) Rubbing alcohol evaporates on your hand.

16. Would a physical change be an example of Cyclic Causality our Domino Causality? Explain why.

A physical change would be considered domino because you can make the compound into 2 again.

17. Give ten different examples of a chemical change.

some examples ** 1) Rust forms on a nail left outside. ** ** 2) Milk goes sour. ** ** 3) You fry an egg. **  ** 4) Your body digests food. ** ** 5) A match is lit. **

18. Would a chemical change be an example of Cyclic Causality or Domino Causality? Explain why.


 * Domino Causality is like chemical change because when you make a chemical change it changes the atoms and turns it to a new element. **

19. How do compounds such as water and sodium chloride (salt) bond together?

They bond chemically

20. The rennett that was added to the milk when we made mozerella cheese in the lab would be considered a catalyst. What is a catalyst and when did we see another example in the lab?

A catalyst is something that makes the reaction go faster.

21. Why would the "gummy bear" explosion in the lab be considered a chemical reaction?

It was domino causality because once you had the explosion, you created new compounds and you can not go back to the gummy bear again.

It is a chemical reaction

22. What are the reactants in the chemical reaction of photosynthesis?

Some reactants in the chemical reaction of photosynthesis include sunlight, oxygen, and carbon.

23. Models of the atom can be represented on paper, on a marble board, and on a stage.

What are advantages of each model? paper - Simple, easy to do marble - More complex, can make the atom building more real acting it out - FUN! What are disadvantages of each model? paper -

marble -

acting it out -

25. Why is "salt" added to the road in the winter months, when roads are slick and icy?

Because it lowers the freezing point of water

26. In the flame test, why is the color of copper chloride a bright blue and the color of lithium chloride bright red?

27. What two reactions did we see in the upper school that were both Combustion Reactions?

The Gummi bear and the flame test

28. A catalyst helps to change hydrogen peroxide into oxygen gas and water. This was an exothermic reaction. Describe the demonstration.

29. What two elements were replaced in the chemical replacement reactions in the upper school lab?

30. What are four clear signs of a chemical reaction - use the upper school demos or any of our labs to explain. color substance

**Questions:**

**#1) Change of State Lab**

**Why would you consider a change of state a physical change?**

**What happens to the molecules of water as they are heated? ( 2 changes)**

**What are some strange properties of water?**

**Why is water so important to life on earth? (plants, animals, bacteria, etc. )**

**Why do trucks put salt on the road when there is a prediction of snow in the forecast?**

**# 2) Mixture Lab (use this lab to answer the questions below)**

**How is a mixture related to a suspension?**

**A snow globe of the NYC would be an example of a mixture, suspension, or solution?**

**Compare a solution and a suspension in the lab?**

**How would you separate a solution?**

**How would you separate a suspension?**

**What is the difference between a mixture and a compound?**

**#3) Ultimate Fizz lab** **What is the advantage of using the data from the entire section compared to the group data?**

**What are the reactants in this reaction?**

**What are the products in this reactions?**

**What are 4 signs of a chemical reaction?**

**What are 4 ways to speed up the chemical reaction?**

**Is this an example of a physical or chemical change?** **#4) Making Chalk Lab**

**What are the reactants in the reaction?**

**What are the products in the reaction?**

**What is a precipitate?**

**How does the appearance of salt in the evaporating dish prove it’s a chemical change and not a physical change?**

**What are other signs that this was a chemical reaction?**

**Was this an example of cyclic or domino causality?**

**#5) Making Cheese Lab** **Use the chemistry terms in the entire unit to explain what happened chemically during the cheese making.**  **(suspension, catalyst, chemical change, reactants, products, curds, whey, rennet, calcium chloride, non pasteurized milk)**

**What specific variables determine whether the cheese will form or not?** **(what could make it not work properly?) What specific steps need to be taken?**

know examples of chemical and physical changes Are the following chemical or physical? Domino or Cyclic? baking a cake chemical ice cube melts into water physical photosynthesis chemical pencil is sharpened physical sugar dissolves in water physical combustion reaction (gummy bear) chemical log is burning chemical water boiling physical mixing sand and water physical making a grilled cheese sandwich physical digesting food in the stomach chemical biting into an apple and chewing physical making mozzarella cheese <span style="color: #008080; font-family: 'Comic Sans MS',cursive; font-size: 16px; line-height: 23px;">chemical baking soda + vinegar = bubbling <span style="color: #008080; font-family: 'Comic Sans MS',cursive; font-size: 16px; line-height: 23px;">chemical making chalk <span style="color: #008080; font-family: 'Comic Sans MS',cursive; font-size: 16px; line-height: 23px;">chemical rusting of metal outside in the rain <span style="color: #008080; font-family: 'Comic Sans MS',cursive; font-size: 16px; line-height: 23px;">chemical breaking a cracker in soup <span style="color: #000080; font-family: 'Comic Sans MS',cursive; font-size: 14px; line-height: 21px;">physical grating cheese for a pizza <span style="color: #000080; font-family: 'Comic Sans MS',cursive; font-size: 14px; line-height: 21px;">physical US Chemical Change Demonstrations a) Why do different compounds react together? (magnesium and oxygen, for example)  <span style="color: #4017d3; font-family: Georgia,serif; font-size: 17px;">Compounds will react because of the number of valence electrons. Magnesium has 2/8 electrons on the outer shell. Oxygen has 6/8 electrons on the outer shell. Like a puzzle, the two atoms fit together nicely. When bonded, the compound is more stable because the electrons in the outer orbital are full.    b) What is a combustion reaction? We saw two different examples. .  <span style="color: #800080; font-family: 'Comic Sans MS',cursive; font-size: 17px;">Gummy Bear <span style="color: #800080; font-family: 'Comic Sans MS',cursive; font-size: 17px;">Mg + Oxygen reaction (bright light) In a combustion reaction the gas Oxygen is involved and released lots of energy in the chemical reaction. Is a combustion reaction cyclic or domino? Explain why. **A combustion reaction is an example of domino causality because once the reaction happens you can't get it back.** c) Why were the flames all different colors in the flame test?   c) What happened in the Copper Replacement reaction? e) When making the Ninja Gas . …   Name the reactants –   <span style="color: #800000; font-family: 'Arial Black',Gadget,sans-serif; font-size: 16px;">hydrogen peroxide H2O2 + Catalyst    Name the products –   <span style="color: #800000; font-family: 'Arial Black',Gadget,sans-serif; font-size: 16px;">water H20 and 02 (oxygen gas)    How was this a chemical change or domino causality?   <span style="color: #bb1b1b; font-family: Arial,Helvetica,sans-serif; font-size: 16px;">Chemical change because new elements are formed in the reaction. It would be difficult to reverse the reaction.    The temperature of the beaker was hot. Was this an endothermic or exothermic reaction?   <span style="color: #bb1b1b; font-family: 'Comic Sans MS',cursive; font-size: 16px;">﻿the temperature increased as the flask felt much warmer. An increase of temperature is EXOTHERMIC. Think Exo or Exit. The energy is being released and making the water warmer. f) What are four major signs of a chemical reaction – What did you see in the demos?  **<span style="color: #24b7b7; font-family: 'Comic Sans MS',cursive; font-size: 18px;">bubbling (a gas) **  **<span style="color: #24b7b7; font-family: 'Comic Sans MS',cursive; font-size: 18px;"> heat or cold temperature change **  **<span style="color: #24b7b7; font-family: 'Comic Sans MS',cursive; font-size: 18px;"> a precipitate on the bottom **  **<span style="color: #24b7b7; font-family: 'Comic Sans MS',cursive; font-size: 18px;"> color change ** **