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Chemistry Unit 1
Unit 1 Flashcards
| Question | Answer |
|---|---|
| Who called the atom the 'ultimate particle?' | Epicurus. |
| What is an atom? | Smallest part of nature; building blocks; made from protons, neutrons, and electrons. They are tiny, dense spheres. |
| What build molecules? | Atoms. |
| What things determine what an atom is like? | Ratio, order, position, and quantity. |
| Can atoms be in any random order. | No, it has to be specific. |
| What are the raw materials for an atom? | Protons and neutrons. |
| In the mid 1800s there were only 53 known elements, how many are there now? | 118. |
| What are the raw materials for a molecule? | Atoms. |
| What is necessary for water to be water? | Bond angle = 104.5; 2H:1O bond ratio; Oxygen is the vertex; Melting point = 0; boiling point = 100, density25 = .986g/mL. |
| What is a chemical formula? | The way of writing a molecule (the numbers belong to the immediate left). |
| What is necessary for hydrogen peroxide? | 2H:2O; mp=-.43; bp=152, d25=1.463g/mL; H->O bond length=98.8; O->O=145.8. |
| What is an unused electron? | Electron not used. It floats above and are in lone pairs. |
| What is the bond length? | The distance from nucleus to nucleus, measured in pm. |
| What does pm stand for? | Picometers, and is 10^-12 (trillionth). Used for measuring bond length. |
| What is a lewis structure? | Using letters instead of circles to represent a molecule. |
| What happens to density when temperature rises? Drops? | If it rises it will go down, and will increase as the temperature drops. |
| What is a structural formula? | Lewis structure. |
| What is a perspective drawing? | Modified lewis structure (wedge and dash). Shows dimension. |
| What is a ball and stick model? | Shows each atom and the bond using a stick. Good for 3D. |
| What is a condensed structural formula? | Like lewis structure but longer. Separates it into groups for clarification. |
| What is a space-filling model | Shows the space occupied by each atom. |
| What is the hydroxyl group? | Makes stuff an alcohol. |
| What is the difference between an atom and an element? | Atom = Singular Element=Plural |
| What is a pure substance? | A substance with definite composition and definite properties. |
| What is definite composition and properties? | Composition - Same bond length, atom count, position, ratios, central atom, orientation, percent composition Properties - Melting point, boiling point, density, specific heat are consistent. Things you ca |
| Is a mixture a pure substance? Why? | No. It doesn't have definite composition and can be changed by physical means. |
| What are physical means? | Color, texture, melting point, boiling point, density, shape. |
| Can atoms be destroyed or created? | No, they can only be rearranged and separated. |
| What is a physical property? Chemical property? | Physical = something you can observe Chemical = when bonds are broken and made. |
| In a chemical reaction, what happens? | Bonds are broken, made, and atoms are rearranged. |
| What is tetrahedral? What is an example? | 4-sided with bond angles of 109.5. Methane is tetrahedral. |
| What is balancing an equation? | Satisfying the law of conservation of matter. Making it so input and output are equal. |
| What is the coefficient? | Multiplier used to balance an equation, goes at the front of the chemical equation. |
| What is the before and after called? | Before=reactants After=products. |
| How do you find molecular weight? | Find the weight of all of the atoms using amu (found on periodic table). |
| How do you find percent composition of a molecule? | Divide the atom amount by the whole and multiply by 100. |
| Know the dichotomous chart for matter. | Okay. |
| What is on the left of the periodic table? The right? The middle? | The left is the metals, the right nonmetals, and the bordering line are the metalloids. |
| What are metalloids? | They are the grey area. They have two faces, metal and nonmetal. |
| What are some key metal characteristics? | Lustrous, malleable, conductors, solid, lose electrons during reactions. If you add an acid, it will turn into a salt with hydrogen gas. If you add oxygen, it will make a brittle salt. |
| What are some key nonmetal characteristics? | Dull, brittle, gases, insulator, gain electrons, creates gas when mixed with oxygen. |
| What is electronegative? | It pulls electrons into its own space. |
| What is a mixture? | Combination of pure substances, it is inconsistent. No chemical bonds, just existing together. |
| What is the difference between a heterogeneous and homogeneous mixture? | Hetero=not even distribution Homo=even distribution |
| When pure substances are combined into a mixture, what physical properties of the pure substances change? | None. |
| What is solubility? | The ability to dissolve in water. |
| How do you separate a heterogeneous mixture? | You can use a magnet, you can decant using a filter, you can use a steam bath, you can use mortar and pestle. Order matters. |
| What order should you separate a mixture? | 1. Use a magnet. 2. Crush up using mortar and pestle. 3. Decant and filter. 4. Do steam bath. |
| What three things do you have when water is introduced to a heterogeneous mixture? | 1. Insoluble material that is denser than water on the bottom. 2. Insoluble but not as dense which floats. 3. Soluble, mixed with the water. |
| How do you measure by difference? | Find the mass of the beaker, and subtract that from the mass of the beaker with the substance. |
| Know how to separate a heterogeneous mixture. | Okay. |
| Know how a steam bath works. | Okay. |
| Why do you not put the evaporating dish directly on the hot plate? | It causes splashing and the high energy water droplets don't form on the bottom. |
| What is better, centimeters or inches? | Centimeters. |
| How do you know how many numbers to record? | Find the smallest number and divide it by two. This gives you the estimated digit. |
| What is the estimated digit? | The number that you estimate on. All the others should be positive. You cannot go past this. |
| The number of significant figures is determined how? | The amount of certain numbers and one estimated. |
| What part of a meniscus do you measure? | The bottom. |
| What is a cm³ equal to? | mL, cc. |
| what is a mL? | It is 1/1000 of a liter, pictured as a cube. |
| When finding density of irregular solids, what do you use? | Water displacement. |
| How much water and substance do you use? | You need enough to cover the substance and enough substance to make the water go up. |
| What is the factor-label method? What goes on top? Bottom? | Used to convert units. The desired unit on top. How much of previous unit to get to top unit on bottom. |
| How much is 1 gram? | 1 ounce=28.35 grams A medium sized paper clip A penny is 2.65 grams. |
| What is mass? Volume? | Mass - how much material in a sample. Volume - space occupied. |
| What is a liter? | A cube of 10cmx10cmx10cm. |
| How big is a centimeter? | About the width of your pinky fingernail. |
| How many centimeters are in an inch? | 2.5cm. |
| How do you find percent error? | ((Observed - Actual) / Actual) x 100 |
| How many significant figures does pi have? | None, it wasn't measured. Significant figures are measured figures. |
| What is an exact number? | Known, counted, or looked up. |
| If you unbend a paper clip, what is the thickness? | .1cm. |
| What does density measure? | How much mass is packed into a certain amount of space. |
| How can you tell something is high density? Think the opposite for low density. | Big molecules, small spaces, more molecules. Probably a metal. |
| How do you find volume if you know density? | Use the factor-label method. |
| Know how to use a Thiele tube. | Okay. |
Created by:
Harrison Smith
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