9 Weeks Test Review

When we added baking soda into the beaker of Acetic Acid. It bubbled for about 10 seconds and then stopped. If we had 20 grams of reactants but only had 15 grams of product what probably happened to the rest of the product?

The remaining 5 grams (mass) of the product was released as a gas into the air during the reaction because we did it in an open system. We know that it produced a gas because of the bubbles that were produced.

How would you know if a precipitate had formed?

The solution would become cloudy and the solid would fall out of it. It could also be a different color.

What are the characteristics of metals

They are shiny, solid at room temperature, malleable, conduct heat and electricity well.

Carbon Monoxide (CO) and Carbon Dioxide (CO2) are both clear gases. Which description most accurately describes the relationship between Carbon Monoxide and Carbon Dioxide?

They are two totally different compounds that include the same elements in different arrangements.

A chemical equation is shown below. 5NaCl + 6H2O → 5Na + 5Cl + 12H + 6O What can you determine from the above equation.

This is an example of the Law of Conservation of Mass because, the number of atoms of each element in the reactants equals the number of atoms of each element in the products.

17. What is the purpose for the bold staircase line on the right side of the periodic table?

To separate metals from nonmetals

Chemical Formulas for Common Household Substances Substance Formula Salt NaCl ammonia NH3 sugar C6H12O6 1. What elements are found in salt? 2. What elements are found in sugar?

1. Na and Cl 2. C, H, and O

Categorize the following with either Compound, Molecule or Element 1. O 2. 2Cl 3. H2SO4

1. O- Element 2. 2Cl- Molecule 3. H2SO4- Compound

Which of the following substances are composed of only one type of atom? If they contain more than one atom, tell me how many they contain. water, gold, salt, sugar

1. water - (2) Hydrogen and Oxygen 2. gold (1) Gold 3. salt (2) Sodium and Chlorine 4. sugar (3) Carbon, Hydrogen and Oxygen

In the formula for Carbon Monoxide, CO, what is the ratio of Carbon to Oxygen? How do you know?

1:1 or 1 to 1 because there is only one of each element present in the chemicals, molecular formula.

If ten grams of Carbon react completely with 20 grams of Oxygen. Based on the Law of Conservation of Mass, how many grams of Carbon Dioxide will be produced?

30 grams, because it cannot be created or destroyed therefore they must equal the same on both sides of the equation. (Balanced Equation)

If this is the formula for an Amino Acid, NH2CHRCOOH, how many Elements & atoms combine to make one molecule of it?

5 Elements (N,H,C, R, O) N- 1 H- 4 C- 2 R- 1 O- 2

What elements are man made/synthetic? Where are they found on the periodic table?

99-118, at the bottom

Accurately describe a heterogeneous mixture?

A heterogeneous mixture contains two or more types of particles which are easily distinguished.

How do you know a chemical equation is balanced?

Each element has exactly the same amount of atoms on each side of the equation.

Which is an example of a mixture? Sodium chloride (NaCl), fruit punch, water (H2O)

No, Sodium Chloride is a compound/molecule Yes, Fruit punch is a mixture No, Water (H2O) is a compound/molecule

Can a phase change produce new compounds? Why?

No, because physical changes occur.

When we mix Sodium Chloride molecules and water molecules, like we did in our experiment (station 3) which of the following would accurately represent what occurred when the molecules dissolved? What happened? @- Sugar and *salt a. @ *@*@*@*@ *@*@*@*@* @ *@*@*@*@ b. ****@@**@@ ****@@**@@ c. @*@@*@@*@ @*@@*@@*@ d. @@@@@@@@ *************

a. @ *@*@*@*@ *@*@*@*@* @ *@*@*@*@ The NaCl (salt) was dissolved in the water, which is a universal solvent. Thus it is distributed evenly throughout the solution. In the other examples they are not distributed evenly. and answer D would be more representative of a heterogeneous mixture (like sand and water or oil and water), not a solution.

Which substance is best classified as a compound? a. Carbon b. Carbon Dioxide c. Gold d. Salt Water

a. Carbon is an element c. Gold is an element d. Salt Water is a homogeneous mixture B is the correct answer because Carbon Dioxide is made up of two different elements. Carbon and Oxygen. CO2

Which best explains the following reaction? 2AgNO3 + Cu2Cl6 → 2AgCl3 + 2CuNO3 a. a physical change occurred, because the reaction produced the same substances b. a chemical change occurred, because the reaction produced two new and different substances. c. a chemical change occurred, because the products and the reactants are the same substances d. a physical change occurred, because the products and reactants are two different substances

b. a chemical change occurred, because the reaction produced two new and different substances. This was our Silver Nitrate and Cupric Chloride that produced a precipitate, thus it was a chemical reaction.

Hydrogen atoms and Oxygen atoms may be represented as shown below. @- Hydrogen *- Oxygen Hydrogen atoms combine with Oxygen atoms in a two-to-one ratio to form the compound water H2O. Which best represents a pure sample of the compound formed between Hydrogen atoms and Oxygen atoms? a. @ * * @ * @ b. ****@@**@@ c. @@*@ @*@ @* d. *@* *@* *@*

c. @@*@ @*@ @*

What do elements of the same vertical column on the periodic table have in common?

chemical properties

Which of these are broken down during chemical, but not physical, changes? elements, mixtures, solutions, compounds

compounds

If Ja'Michael and Scott performed the same exact experiment testing the law of conservation of mass, but both students had different results. Which best explains why this might have happened? a. They both used the same set of procedures correctly. b. Their hypothesis was incorrect. c. They contaminated their products by spitting in them. d. They measured their reactants and products incorrectly.

d. They measured their reactants and products incorrectly.

A student passes a magnet over 10 grams of a powder. Four grams of the powder stick to the magnet, while 6 grams do not. This would be an example of what type of substance?

mixture

What might indicate a chemical change had occurred if two clear solutions are mixed together in a test tube?

A precipitate forms Heat is released Bubbles form (a gas is released) A color change

What are some examples of a chemical change?

Adding Silver Nitrate to Cupric Chloride (produces a precipitate) Burning paper (it changes from paper to ashes) Adding Calcium Nitrate to Water (produces heat)

Which elements will most likely have similar physical properties to Helium (He)? Why?

Any of the Noble Gases, because they are in the same group. Group 18

What element has the greatest atomic number Potassium, Calcium, Sulfur or Chlorine?

Calcium

What are some examples of a physical change?

Change in state Change in shape Change in size

What physical property would be most important in choosing the right chemicals for a fireworks show?

Color

Which does Calcium dioxide (CaO2) represent?

Compound

Copper is an example of an

Element

What describes how physical properties were used to produce the periodic table?

Elements are arranged into groups based on similar properties.

Explain the difference between an element and a compound?

Elements cannot be broken down because they are a single atom, while compounds can because they join together multiple types of atoms.

Which elements are most likely to form compounds? Elements in groups 17 and 18 Elements in the lanthanide and actinide series Elements in groups 2 and 3 Elements in groups 1 and 7

Elements in groups 1 and 7 because of the number of electrons in their outer valence electrons.

How does the zig-zag line on the periodic table help indicate properties of elements?

Elements located on the left of the zig-zag line are good conductors of heat and electricity.

If you find a stone from an unknown element. Which is the best way to determine which element was used to create the stone?

Find it's density

What group listed below is the most chemically reactive? Why? Group 2, 1,13, or 18.

Group 1 is the most reactive because it wants to lose one electron so that it's remaining valence electron shell will be full. Group 18 is least reactive because it is the Noble Gases. Groups 2 and 13 have 2 and 3 valence electrons so they are going to need to lose more electrons than group 1 so they are reactive but not as reactive as group 1.

An element that readily reacts with an alkali metal most likely belongs to what group? Why?

Group 17, because group 1 only needs to get rid of one electron and group 17 needs only one to make it's valence electron shell full.

If you heat Gold to 1,948°F, it becomes a liquid. What specific type of property is this? Is this an example of a physical or chemical change? Why?

Melting Point, this is a physical change because it is still Gold.

Describe what a mixture is.

Mixtures are made of different elements that are not all chemically bonded together.

How does the total amount of mass present in a chemical reaction change during a chemical reaction?

It doesn't based on the Law of Conservation of Mass, it remains the same during the reaction.

When you heat water to 100 degrees what happens?

It has reached it's boiling point and becomes a gas.

How does reactivity change in a group

It increases as you go down the group.

How can you most accurately define a compound?

It is composed of two or more atoms of different elements that have been chemically combined together.

If you fill a balloon with Helium what changes the most as a balloon is inflated: Its density, conductivity, temperature or volume?

It's Volume

Which is/are the best example/s of a heterogenous mixture? sugar, brass, salad, salt water, sand and water

Salad & Sand and Water

Which substance/s are compound/s? orange juice, sugar, salt water, hydrogen, water

Sugar and Water are compounds

How would you best describe how the physical properties of elements generally vary across a period?

The elements on the left side of a period have metallic properties, while the elements on the right side of a period have more nonmetallic properties.

According to the Law of Conservation of Mass, in a chemical reaction, which is true about the atoms present in the reactants compared to the atoms in the products?

The number of atoms present in the reactants must equal the number of atoms in the products. Ex: 2AgNO3 + Cu2Cl6 → 2AgCl3 + 2CuNO3