Matter And Energy Density 2 Density the amount

  • Slides: 68
Download presentation
Matter And Energy

Matter And Energy

Density 2. Density: the amount of matter packed into a volume. Equation: 3. Units

Density 2. Density: the amount of matter packed into a volume. Equation: 3. Units for density include: 1. A. B. g/m. L g/cm 3 m d v

cork water liquid mercury brass nut

cork water liquid mercury brass nut

4. Sample problems Find the density of an object in g/cm 3 if the

4. Sample problems Find the density of an object in g/cm 3 if the mass is 4. 370 g and the volume is 2. 12 cm 3. m= v= D= A.

A cube of metal has a density of 4. 51 g/cm 3. If 95.

A cube of metal has a density of 4. 51 g/cm 3. If 95. 7 grams of the metal is added to 145 m. L of water in a graduated cylinder, to what volume would the water rise? m= Hmm tricky v= D= B.

A cube of metal has a density of 0. 997 g/m. L and volume

A cube of metal has a density of 0. 997 g/m. L and volume of 3019 m. L. What is the mass of the cube? m= v= D= C.

An aluminum block has the mass of 57 grams. The volume of the block.

An aluminum block has the mass of 57 grams. The volume of the block. 0211 L. What is the density of the aluminum block? What’s the plan? Convert the. 0211 L to m. L and then solve the problem by dividing 57/21. 1 D.

1 K H D base You move 3 spaces to the right da 2

1 K H D base You move 3 spaces to the right da 2 3 c m

i. m= v= D= 0. 0211 L = 21. 1 m. L

i. m= v= D= 0. 0211 L = 21. 1 m. L

E. You enter a pawn shop looking to purchase a gold coin. The shop

E. You enter a pawn shop looking to purchase a gold coin. The shop keeper shows you an amazing looking coin, but you are not sure if it’s 100% gold or not. You purchase the coin for a high price anyway, and test the coin to see if it’s pure gold. Wikipedia says that the density of gold is 19. 32 g/cm 3.

You bring your coin to chemistry class to conduct an experiment. You fill a

You bring your coin to chemistry class to conduct an experiment. You fill a large graduated cylinder up to 30. 0 m. L and carefully drop the coin in. The water rises to 35. 6 m. L. You place the coin on a balance and find it to be 35. 4 grams. What is the density of the gold coin? Should you be happy with your purchase or go back to complain?

m= v= D=

m= v= D=

Matter: anything that takes up space, has mass, and shows inertia. 1. Inertia: resistance

Matter: anything that takes up space, has mass, and shows inertia. 1. Inertia: resistance for any object to change its state of motion. Also referred to as Newton’s First Law of Gravity. A. 2. The basic piece of matter is the atom.

The atom can be broken down into smaller parts called subatomic particles. 3. A.

The atom can be broken down into smaller parts called subatomic particles. 3. A. B. C. D. Subatomic particles include: protons, neutrons, and electrons. Proton: positively (+) charged subatomic particle. Electron: negatively (-) charged subatomic particle. Neutron: Neutral charged subatomic particle.

E. 4. Nucleus: center of atom made of protons and neutrons. When two or

E. 4. Nucleus: center of atom made of protons and neutrons. When two or more atoms form a bond, then a molecule is formed.

2. Nucleus 1. Atom Electron Proton Neutron

2. Nucleus 1. Atom Electron Proton Neutron

Water Phosphatidylinositol Methane

Water Phosphatidylinositol Methane

Phases and Phase Changes Three widely known phases: solid, liquid, gas. Important to know

Phases and Phase Changes Three widely known phases: solid, liquid, gas. Important to know what the molecules are like in each phase 1. A. B. C. Solid: molecules are packed tightly together, but can still vibrate. Liquid: molecules can move around, but are still close to each other. Gas: molecules can move around freely, and are not close to each other.

(a) Solid (b) Liquid (c) Gas

(a) Solid (b) Liquid (c) Gas

Plasma: state of matter where electrons are stripped from atoms. Occurs at high temperatures.

Plasma: state of matter where electrons are stripped from atoms. Occurs at high temperatures. 2. A. Ex: florescent light, flame, lightning, sun. Plasma TV’s? Made of millions of tiny “cells” or “florescent lamps. ”

Pure Substances Made up of only one material. The material can be an element

Pure Substances Made up of only one material. The material can be an element or a compound. 1. 2. A. B. If it is an element, then it’s found on the periodic table. An element is a pure substance made of only one kind of atom.

Diatomic Gases: gases that are always found in pairs. 3. A. Include: H 2,

Diatomic Gases: gases that are always found in pairs. 3. A. Include: H 2, N 2, O 2, F 2, Cl 2, Br 2, I 2 Allotropes: different forms of the same element. 4. A. Example: diamonds and graphite.

Diamond Inclusions

Diamond Inclusions

5. Compounds: form when two different elements join chemically. A. When a chemical reaction

5. Compounds: form when two different elements join chemically. A. When a chemical reaction occurs, both physical and chemical properties are highly likely to change.

Mixtures: homogeneous and heterogeneous mixtures 1. 2. 3. A mixture is a physical combination

Mixtures: homogeneous and heterogeneous mixtures 1. 2. 3. A mixture is a physical combination of two substances. The different parts can be separated physically using various methods. No new substances should be occurring.

Heterogeneous mixture: a mixture that is not equally mixed. 4. A. B. Different regions

Heterogeneous mixture: a mixture that is not equally mixed. 4. A. B. Different regions have different physical properties. Ex: Italian dressing, pepperoni pizza, chocolate chip cookies.

Homogeneous mixture: mixture that has particles evenly mixed. 5. A. B. C. D. E.

Homogeneous mixture: mixture that has particles evenly mixed. 5. A. B. C. D. E. All phases of matter (solid, liquid, and gas) can be in a homogeneous mixture. Ex: air, gasoline, 14 -karat gold Homogeneous metals are called alloys. Homogeneous liquids are called solutions. Solutions cannot be separated through a filter.

Carat measures two things: mass and purity. Carats for rings are based on 24

Carat measures two things: mass and purity. Carats for rings are based on 24 -carat scale. 24 carat is pure gold. 14 carat-gold rings would have slightly more than half gold. 10 carat rings would be slightly less than half gold.

Brass is not a pure metal. It’s a homogeneous mixture of copper and zinc.

Brass is not a pure metal. It’s a homogeneous mixture of copper and zinc.

Compound or Element

Compound or Element

Compound or Element and Pure Substance or Mixture

Compound or Element and Pure Substance or Mixture

Compound or Element and Pure Substance or Mixture

Compound or Element and Pure Substance or Mixture

Compound or Element and Pure Substance or Mixture

Compound or Element and Pure Substance or Mixture

Compound or Element and Pure Substance or Mixture

Compound or Element and Pure Substance or Mixture

Mixtures Vs. Compounds 1. 2. Mixtures are physical combinations. Compounds are chemical combinations. Compounds

Mixtures Vs. Compounds 1. 2. Mixtures are physical combinations. Compounds are chemical combinations. Compounds change properties, while mixtures have a combined property. Ex: Alloys are normally stronger (Steel made of iron and carbon). Methanethiol (mercaptan) gas added to natural gas. Methanethiol still smells.

Atoms in compounds always combine in whole numbers. No fractions or decimals. 3. A.

Atoms in compounds always combine in whole numbers. No fractions or decimals. 3. A. 4. 5. Ex: H 2 O. CO 2. You never see H 3. 5 O or CO 9. 2 To separate a compound back into its pure substances, then you must use other chemical reactions. Mixtures can be separated using physical methods.

Physical Vs. Chemical Property Chemists - and you - will study physical and chemical

Physical Vs. Chemical Property Chemists - and you - will study physical and chemical properties. In order to study both you must be able to determine the difference. 2. Physical property: observations made without changing the composition or identity of a substance. 1.

H 2 O Ex: ice is made of what molecule? _______ 0ºC or 32ºF

H 2 O Ex: ice is made of what molecule? _______ 0ºC or 32ºF B. Ice will melt at what temp? ______ C. What is the molecule after when ice melts to H 2 O water? _______ Think of your own example of a physical property. A.

Physical properties can be categorized as either extensive or intensive. 3. Extensive physical properties:

Physical properties can be categorized as either extensive or intensive. 3. Extensive physical properties: a property where the amount of matter is important. A. i. Example: mass, volume, length, and size. Intensive physical properties: a property where the amount of matter is not important. B. i. Example: color, density, melting point, boiling point.

C. When remembering extensive and intensive properties think of cutting a substance in half.

C. When remembering extensive and intensive properties think of cutting a substance in half. If you are asked if color is an extensive or intensive property how could you tell? You must remember that extensive properties depend on the amount of matter present. Then ask yourself, if you have a red ball, and you cut the ball in half, will the color of the two halves be the same? Yes. Intensive property. How about mass? If you have a red ball and you cut it in half, will the halves have the same mass? No – so mass is an extensive property.

Chemical properties: how a substance reacts with another substance. 4. A. When atoms and

Chemical properties: how a substance reacts with another substance. 4. A. When atoms and molecules react with each other to form new molecules, physical properties often change. Chemical reactions can be used to change one substance into another. This does not mean that you can take lead and turn it into gold. That takes a nuclear reaction. 5.

Chemical reactions have two sides 6. N 2 + H 2 NH 3 A.

Chemical reactions have two sides 6. N 2 + H 2 NH 3 A. B. C. The left side of the arrow (with the N 2 + H 2) is called the reactant side. The right side of the arrow (with the NH 3) is called the product side. The entire reaction is called a chemical equation.

What does the chemical equation tell us? 7. A. What you start with what

What does the chemical equation tell us? 7. A. What you start with what you end with

Classify the following as either a chemical or physical property: 1. Color 2. Flammability

Classify the following as either a chemical or physical property: 1. Color 2. Flammability 3. Hardness 4. Odor 5. Taste

Physical Change vs. Chemical Change A physical change happens when you do a reaction,

Physical Change vs. Chemical Change A physical change happens when you do a reaction, but no new substance occurs. A chemical change happens when you do a reaction, and a new substance does occur. 1. 2. A. When a new substance is formed it is hard, unless you use a lot of energy, to go back to the original substance.

Example: You have a log burning outside, it releases gas and you are left

Example: You have a log burning outside, it releases gas and you are left with a pile of ash. It would be impossible to remake that log because you would need to trap all the gas being released. Signs of a chemical reaction include: B. C. i. ii. iii. iv. Bubbling temperature and/or color changes formation of a solid when mixing two liquids. Odor released

Classify the following as either a chemical or physical change: 1. 2. 3. 4.

Classify the following as either a chemical or physical change: 1. 2. 3. 4. 5. Boiling water becomes steam Butter turns rancid Burning of wood Mountain snow melting in spring Decay of leaves in winter

Energy 1. Energy: a quantity used to show the amount of work done.

Energy 1. Energy: a quantity used to show the amount of work done.

Different forms of energy 2. Kinetic energy: the energy of motion. Also defined as

Different forms of energy 2. Kinetic energy: the energy of motion. Also defined as a work needed to move an object of some mass to a specific speed. i. iii. Equation for kinetic energy = ½ mv 2. m = mass v = velocity

B. i. Potential energy: stored energy Examples: stretched rubber band, rollercoaster at the top

B. i. Potential energy: stored energy Examples: stretched rubber band, rollercoaster at the top of a hill, and a battery.

Energy can also be transformed. 2. Different types of energy include: mechanical, thermal, and

Energy can also be transformed. 2. Different types of energy include: mechanical, thermal, and chemical. Ex: mechanical E is associated with motion or position of an object Ex: Thermal E is the movement of heat from warmer to cooler objects. Ex: chemical E is the breaking and reforming of chemical bonds. A.

Conservation of Energy: states that energy is never created nor destroyed. Energy is always

Conservation of Energy: states that energy is never created nor destroyed. Energy is always transformed. In a chemical reaction, if energy in the form of heat is given off, the reaction is exothermic. 3. 4. A. Example equation Fe 2 O 3(s) + 2 Al(s) Al 2 O 3(s) + 2 Fe(l) + energy

B. Example of exothermic reactions: wood burning or fireworks exploding. Must have a chemical

B. Example of exothermic reactions: wood burning or fireworks exploding. Must have a chemical change occurring!

In a chemical reaction, if energy is absorbed, then it is considered endothermic. 5.

In a chemical reaction, if energy is absorbed, then it is considered endothermic. 5. After a reaction if the substance feels cold, then it’s most likely endothermic. B. Example equation: Ba(NO 3)3∙ 8 H 2 O + 2 NH 4 SCN + heat Ba(SCN)2 + NH 3 +10 H 2 O A.

C. D. A substance can also get warmer, too (quite confusing). Ex: Ice +

C. D. A substance can also get warmer, too (quite confusing). Ex: Ice + heat water. This is an endothermic reaction. Water + heat steam.