# Unit 2 ## Questions to Ask Ms.Keras 1. How do you tell the difference between mechanical mixtures and a mixture/solutions? 2. Are qualitative properties and physical properties basically the same thing? 3. Are the families the akali, akaline, halogens and noble gases? 4. What was the zero sum rule? 5. Do all atoms want to get rid of only the outer shell electrons? 6. What are the elements I need to know? 7. What is the difference between an atom and an ion? ## Page 178, Questions 3 - 10. Alloys: When two or more types of metals are mixed together. Solder Materials: Used to join together metal components, such as wires in electrical circuits and copper pipes in building, like glue. 2. **Use the particle theory to explain why water changes from a solid to a liquid when it is heated.** As water is heated, the particles or atoms gain energy, thus begin to spread apart and moving quicker, and when particles are spread decently apart, that state is called a liquid state. 3. **Give 3 examples of a pure substance** 1. Water 2. Milk 3. Apple juice 4. **Give three examples of a mixture** 1. Soup 2. Cereal with milk 3. Granorla Bar 5. **Describe a Mechincal Mixture** A mechinal mixture could be something like a cereal with milk, where you can see the cereal and milk easily. 6. **Describe a Solution** A solution could be something like apple juice, where there are different types of particles present, but are evenly mixed. 7. **Use a Venn diagram to compare mechanical mixtures and solutions** |Mechnical Mixtures|Both|Solutions| |:-----------------|:--:|--------:| |Apple Juice| 8. **Identify each of the following as a mechanical mixture or a solution** a. a pane of clear glass. **Solution** b. chocolate chip ice cream. **Mechanical Mixture** c. clear apple juice. **Solution** d. a pizza. **Mechanical Mixture** e. garbage in a garbage can. **Mechanical Mixture** 9. **What kind of alloy makes an effective solder material?** Tin and lead make an effective solder material, as it is fluid at high temperatures but solidifies quickly. 10. **Lead is not often used in solder anymore. Explain why not.** As lead is a heavy metal, it causes radioactive damage to humans, such as brain damage, which makes it harmful and unsafe. ## Pages 182 Questions 1 - 5 1. **Explain the difference between a qualitative property and a quantitative property** A qualitative property is a property that is of the **qualities** of an thing, for example, metal, which is very shiny and hard. A qualitative property cannot be measured. A quantitative property is something that can be measured, like the temperature of the metal, the mass or size of the metal. 2. **A student recoreded the following observations about a T-shirt. Classify each observation as a qualitative property or a quantitative property, and give reasons for your answers** a. It is red and grey in colour. **Qualitative**, as it cannot be measured and is a quality of the object. b. It is 60 cm long. **Quantitative**, as it its measured in cm and is the length of the object. c. It is soft and strectchable. **Qualitative**, it is a property of the material. d. It will shrink in 70o water. **Qualitative**, it is a property of the material. **Ask MS KERAS** 3. **What physical properties are important for the materials used to make mountain bikes?** The bikes should be light weight, hard, durable and comfortable. 4. **List four physical properties of each of the following** * a piece of copper wire 1. its shiny 2. hard 3. bendable 4. smooth * 500 g of butter 1. soft 2. easy to cut through 3. really creamy 4. smells like cheese and milk * a glass of milk 1. opaque 2. white 3. liquid 4. non-viscous * a candle 1. hot 2. bright 3. waxy 4. soft * a piece of aluminum foil 1. shiny 2. smooth 3. grey 4. solid * a spoonful of sugar 1. powdery 2. white 3. sweet 4. solid * toothpaste 1. somewhat viscous 2. opaque 3. taste like the flavour of the toothpaste 4. squishy 5. **In each of the situations below, it seems that a new substance may have been produced. Explain why each situation represents a physical change.** * A tailor makes a new suit out of a piece of fabric - it is still a piece of the same fabric, thus no new substances have been produced, this is a physical change. * A chef makes a salad out of lettuce, tomatoes , and cucumbers - This is a mixture of different substances, but no new substances have been created, this is a physical change. * A mechanic builds a boat engine out of a lawnmower - The mechanic's lawnmower are still made of the same parts of the boat engine, thus no new substance was created. * A chemist boils salt water until only salt crystals are left. - The water evaporated but the salt was already present in the water, thus its a pyhsical change. * A child makes juice by adding water to juice concentrate - Juice already contains water, and adding more water just water downs the solution, but does not create a new substance. ## Pages 186 Questions 1 - 7 1. **Describe the diference between a physical change and a chemical change** In a physical change, no new substance is created, while a new substance is created in a chemical change. 2. **Explain why water freezing is not a chemical change.** As freezing water is just changing the state of water, water is still water, so there has been no new substance created. 3. **Classify each of the following as a physical or a chemical property** - metalic lustre **CHEMICAL** - boiling point **PHYSICAL** - explodes when ignited **CHEMICAL** - changes colour when mixed with water **CHEMICAL** 4. **Classify each of the following as a physical change or a chemical change. For each chemical change, explain how you can tell that a new substance has been formed** - Water boils and turns into steam - Physical change, there is not new substance - Wood is sawed and made into a toy box - Pyhsical change, the toy box is still made up of the same wood - Firewood burns and ashes remain - Chemical change, the ashes are the new substance - Orange drink crystals are stirred into a pitcher of water - Physical change, there is no new substance being created. - Sugar eggs, and flour are mixed and baked into cookies - Chemical change, the cake is the result of the ingredients reacting with bacterias and each other 5. **What evidence is there that a glowstick works as a result of a chemical change?** The glowstick glows due to the two chemicals at both ends meeting each other, which a new lumious liquid is made. 6. **When a candle is lit and allowed to burn for 15 minutes, some wax drips and colelcts at the base of the candle, and the candle becomes shorter** - Did you observe any physical changes? Explain - yes, as the candle got shorter due to the flame buring it off. - Why did the candle become shorter? What happened to the missing section of the candle - the missing section of the candle turned into liquid due to the heat melting it. - Did you observe any evidence of chemical change? - **ASK MS KERAS** 7. **Think about each of the following situations and describe one chemical change that is occurring. provide evidence of the chemical change** - A driver starts the car in the drive way - The gasoline is being burned of to created electricity, and produces fumes that exit the car. - A bathroom cleaning product removes a stain in the sink - The chemicals in the product reacts with the stain, and the result is the removal of the stain. - Bubbles form when baking soda is mixed with lemon juice - The bubbles are the result of the chemical change - Cookies baking in the oven give off a delicious aroma - The ingredients are reacting with the heat to create the smell. - A match is struck and ignites - The friction of 2 substances sets off a chemical reaction that allows the match to light on fire - Bleach turns a red towel white - The bleach chemicals react with the pigments in the towel, resulting in the removal of the colour of the towel. - A banana tastes sweeter as it ripens - The chemicals in the banada react to heat and age, producing glucose, which makes it sweeter. ## Pages 215 Questions 1-10 Metalliod: an element that has properties of both metals and non metals Non metal: an element, usually a gas or a dull powdery solid, that does not conduct heat or electricity. Element: a pure substance that cannot be broken down into a simpler chemical substance by any physical or chemicl means Compound: a pure substance composed of two or more different elements that are chemically joined 1. **Which of the following substances are elements? Explain how you determined your answer** - bronze - tin - chromium - solder - propane - arsenic - nickel 2. **What is the difference between an element and a compound?** 3. **A white powder, when heated, produces a colourless gas amd a black solid. is the white powder an element? Give reasons for your answer** ## Pages 225 Questions 1 - 10 ## Pages 233 Questions 1 - 7 1. **Dalton theorized that matter is made of tin, indivisible particles called atoms. In what way did the theories of each of theses scientist support or differ from Dalton's theory?** - J.J Thomson - Also agreed in the existence of the atom, but also explainied that there are even smaller particles called the electron - Ernest Rutherfort - Also agrered in the existence of the atom, but also explainied that there was an nucleus, that was the weight of the atom, which contained both protons and neutrons ## Pages 261 Questions 1 - 6 ion: A particle that has either a positive or a negative charge cation a positvely charged ion anion: a negatively charged ion Ionic compound: a compound that onsists of positvely and negatively charged ions Diatomic molecule: molecules that only consist of 2 atoms, of either the same or different checmical elements Molecule: two or more atoms of the same or different elements that are chemically joined together in a unit Covalent: When they share a bond Hydroxide: OH Carbonate: CO3 Imidogen: HN **All metals are cations** 1. **The chemical formula for baking soda is NAHCO3. Answer the following questions about baking soda** - How many elements does it contain? - 4 elements, Sodium, Hydrogen, Carbon, Oxygen - How many atoms of each element are in this formula? - 1 Sodium - 1 Hydrogen - 1 Carbon - 3 Oxygen - Does baking soda contain metallic and non-metallic elements? Which ones are which? - Metals - Sodium - Non - metals - Oxygen - Carbon - Hydrogen 2. **Consider the following substances: hydrogen gas (H2), carbon dioxide (CO2), Sulfur (S8), neon (NE), and propane (C3H8). Which substance(s) are:** - Elements? - Sulfur, Neon, Hydrogen - Compounds? - Propane, Carbon dioxide - Atoms? - All of them - Molecules? - Sulfer, Carbon dioxide, Hydrogen, Propane 3. **What does the term "diatomic molecule" mean?** molecules that only consist of 2 atoms, of either the same or different checmical elements. 4. **List the seven diatomic molecules:** 1. H2 Hydrogen 2. O2 Oxygen 3. F2 Flourine 4. Br2 Bromine 5. I2 Iodine 6. N2 Nitrogen 7. Cl2 Chlorine 5. **Gasoline contains a mixture of compounds called hydrocarbons. They include molecules with the following formuals: pentane (C5H12), hexane (C6H14), heptane (C7H16), and octane (C8H18). Explain why "hydrocarbon" is a good name for this group of compounds**. They all have alot of hydrogen and carbon molecules, so hydrocarbon is a good name for them. 6.   Question 6 - Explain the difference between an atom and an ion an atom is a particle that has an nucleus, and is neither a positive nor positive charged, an ion is an atom that is charged - Give an example of an atom and an ion, and draw a Bohr-Rutherford diagram of each - ddd ## Pages 261 Questions 7 - 11 7. **Write the chemical formula for each of the following compounds. Start the formula with the first element listed in each statement below and follow with the next element. The ratios in which the element combine are given in each statement.** - Ammonia, commonly found in window cleaning liquids, is formed when one nitrogen atom combines with three hydrogen atoms. - NH3 - Carbon dioxide is formed when one carbon atom combines with two oxygen atoms - CO2 - When there is insufficient oxygen, one carbon atom combines with only one oxgen atom, forming the deadly gas carbon monoxide - CO - When hydrogen gas is burned, two atoms of hydrogen combine with one atom of oxygen to form a common substance - H2O - Rubbing alcohol is formed when three atoms of carbon combine with eight atoms of hydrogen and one atom of oxygen. C3H8O 8. **An atom of calcium loses two electrons to become an ion. What kind of ion is a calcium ion?** - Its an cation 9. **Write chemical symbol for a calcium ion - Ca2+ 10. **Distinguish between molecular elements, molecular compounds, and ionic compounds.** - Ionic compounds are 2 or more ions being combined - molecular elements are elements that have 2 or more of the same element bonding - molecular compounds are made up 2 or more of the same or different elements 11. **State whether each of the following is a molecular element, molecular compound, or ionic compound** - Iodine (I2) - Molecular element - Sodium chloride - ionic compound - Vinegar - ionic compound - Propane - molecular compound ## Pages 266 Questions 1 - 10 1. **A piece of jewellery that is made of 14kt gold contains 14 parts gold and 10 parts copper** - What percentage of the jewellery is gold? - Do gold and copper form compounds in the jewellery? Explain - Explain how the 14kt gold used to make jewellery is different from the element gold 2. **Metal alloys are sometimes described as solid solutions. Explain how an alloy is similar to a solution such as salt water** An alloy is also a solution, of two metals, a homogeneous mixture, justl like salt water 3. **Write the common name for each of the following compounds** - sodium hydroxide - lye - O3 - ozone - sodium chloride - table salt - CO2 - dry ice - sodium hydrogen carbonate - baking soda - calcium carbonate - limestone 4. **Write the chemical name for each of the following compounds - Muriatic acid - HCl - Vinegar - C2H4O2 - Potash - KCl - Quicklime - CaO -