SNC1D Chemistry Unit Review Answers PDF

Name: ___________________ Date: ___________ SNC1D Chemistry Unit Review 1. Chemistry Basics a. What are physical properties and chemical properties? Give two examples of each. Physical proper...

Name: ___________________ Date: ___________ SNC1D Chemistry Unit Review 1. Chemistry Basics a. What are physical properties and chemical properties? Give two examples of each. Physical property is a property we can determine without permanently changing the substance, for example: colour, smell, melting point Chemical property is a property that can only be determined by permanent changing the substance, for example: flammability, toxicity, reactivity b. What are physical changes and chemical changes? Give two examples of each. A physical change is a reversible change (usually a change of state), for example: melting ice or vaporizing water. A chemical change is a non-reversibly change, for example: burning wood, frying an egg. c. What is a quantitative observation and what is a qualitative observation? Give two examples of each. Quantitative observation has a specific numerical value, while qualitative does not. For example, 15 kg or a dozen roses is quantitative; red roses or fishy smell is qualitative. d. What are the three common states of matter and how do particles in each state behave? What is plasma? Solids: particles are packed closely together, and vibrate. Liquids: particles are a little further apart than in solids, and flow past each other. Gases: particles are far apart and fly past each other. Plasma is a superhot, high-pressure gas. The sun is a ball of plasma. e. What are the three subatomic particles? What is their charge and size? Where are they located in relation to the atom? Protons: positive subatomic particles with a mass of 1. They are located in the nucleus of the atom. Neutrons: neutral subatomic particles with a mass of 1. They are located in the nucleus of the atom. Electrons: negative subatomic particles with a mass of 1/1838. They are orbiting around the nucleus. f. What is the difference between an element, a compound, and a mixture? An element is a type of atom. A compound is a combination of two or more different atoms (elements) bound together. A compound is a pure substance. A mixture is a combination of different particles in the same space (not bound together).  g. Are all molecules also compounds? Why? A molecule is any combination of two or more atoms. Not all molecules are compounds. A molecule might be composed of two or more of the same element. For example, H2 or O2 are molecules, but not compounds. h. What is the difference between a homogeneous and heterogeneous mixture? Give an example for each. A homogeneous mixture has one phase (meaning, it looks like just one substance). An example is milk or apple juice. A heterogeneous mixture has multiple phases (different parts are visible). An example is chicken soup or pizza. i. Determine which of the following are elements, compounds, and mixtures: water, table salt (NaCl), iron (Fe), tea, milk, magnesium (Mg), alcohol (C2H6O) Elements: iron, magnesium Compounds: water, table salt, alcohol Mixtures: tea, milk 2. Periodic Table a. What is the “periodic table”? How is it arranged? The periodic table is a chart of all the elements, arranged according to atomic number (the number of protons). b. Who is credited with first organizing our modern periodic table? Dmitri Mendeleev c. Where are the metals found on the table? Where are the non-metals found? What are two properties of each? Metals are on the left of the “staircase”. Non-metals are on the right of the “staircase” (except hydrogen). Metals want to lose electrons, they are shiny, they conduct electricity. Non-metals like to gain electrons, generally do not conduct electricity. d. What is a metalloid? Where is it located on the periodic table? Metalloids are elements that have properties of both metals and non-metals. They are located along the “staircase” of the periodic table. e. What are the rows of a periodic table called? What are the columns called? What do the rows and columns tell us about the elements in them? Rows are periods, columns are groups. Rows tell us how many orbitals an atom has. Columns tell us how many valence electrons an atom has.  f. Why are noble gases non-reactive? Noble gases are non-reactive because they already have a full valence shell. g. How are alkali metals different from alkaline earth metals? Alkali metals have one valence electron while alkaline earth metals have two. Alkali metals are more reactive. 3. Atomic Properties a. Which number determines the type of element? atomic number (protons) b. What is atomic mass? sum of protons and neutrons c. What is an isotope? same element but different number of neutrons resulting in a different mass d. Which element has a mass of 6.9? lithium e. Which element has an atomic number of 8? oxygen f. How many neutrons do the following elements have: magnesium 12, beryllium 5, aluminum 14, phosphorus 16 g. How many protons do the following elements have: chlorine 17, sodium 11, helium 2, neon 10 h. How many electrons does lithium have? 3 electrons How many valence electrons does it have? 1 valence electron i. What is the difference between an anion and a cation? anion is negatively-charged because it gained electrons; cation is positively-charged because it lost electrons. j. Which types of elements usually become anions and which become cations? Non-metals become anions, and metals become cations. 4. Structures a. Draw the Bohr-Rutherford diagram for the following atoms: sodium, fluorine, aluminum  b. Draw the Bohr-Rutherford diagram for the ions of the following elements: magnesium, chlorine, oxygen c. How is a Lewis diagram different from a Bohr-Rutherford diagram? Why is it more commonly used? Lewis shows only the element symbol and valence electrons, while Bohr-Rutherford is detailed and shows all the subatomic particles and shells. Lewis is more common because only valence electrons play a role in chemical reactions, so they are the most important for chemistry, and the only ones that need to be shown. d. Draw Lewis diagrams for the following atoms: oxygen, helium, phosphorus e. Draw Lewis diagrams for the ions of the following elements: lithium, selenium, boron [Li]+ [B]3+ 5. Development of the Atom & Reactions a. Summarize the contributions of the Ancient Greeks, Dalton, Thomson, Rutherford, and Bohr in the development of the atomic model. Ancient Greeks: the concept of a tiny, indivisible atom. Dalton: the atomic theory Thomson: electron (and “blueberry muffin” model) Rutherford: a positive nucleus (and the “planetary” model) Bohr: electron orbitals/energy levels  b. What did Thomson use to discover the electron? A cathode ray tube (a vacuum tube with electricity flowing through it). c. What is the name of Rutherford’s famous experiment? What did he discover? The gold-foil experiment. He discovered that an atom has a positively-charged core (the nucleus). Later, Rutherford and his team discovered the proton and the neutron. d. State three points from Dalton’s Atomic Theory All matter is made up of atoms. Atoms cannot be created, destroyed, or divided. All atoms of the same element are identical in mass and size. 6. Bonding & Reactions a. Which types of elements combine to form ionic bonds? Which combine to form covalent bonds? What is the difference between these bond types? Metals and non-metals make ionic bonds. Two or more non-metals make covalent bonds. Ionic bonds transfer electrons and the atoms become charged ions. They are held together by their opposite charges, which attract each other. Covalent bonds share electrons, and holds atoms together by the fusion of their valence shells. b. Which compound would form from the reaction of lithium and fluorine? Draw the Lewis diagram and write the formula. Name the compound. LiF lithium fluoride c. Which compound would form from the reaction of magnesium and chlorine? Draw the Lewis diagram and write the formula. Name the compound. MgCl2 magnesium chloride d. Which compound would form from the reaction of hydrogen and oxygen? Draw the Lewis diagram and write the formula. Name the compound. H2O dihydrogen monoxide  e. Which compound would form from the reaction of carbon and hydrogen? Draw the Lewis diagram and write the formula. Name the compound. CH4 carbon tetrahydride f. Which compound would form from the reaction of nitrogen and chlorine? Draw the Lewis diagram and write the formula. Name the compound. NCl3 nitrogen trichloride g. What is a combustion reaction? Burning something in the presence of oxygen. h. What is the difference between synthesis and decomposition? Synthesis is a reaction where two or more substances combine to form a new product. Decomposition is where one substance breaks down to form two or more products. i. Identify the reactants and products of the following chemical equation: H2O + CO2 🡪 H2CO3 reactants product