What’s The Matter? Unit for 7th grade science 2014-2015

Dear parent/guardian,

Here is the Matter unit that we will work on in January. It does include several lab activities, a research project and a written test. Please look over this unit and outline and sign that you have seen what your child is learning in science. Help is always available after school for any student that needs it. Your child gets a 10 pt. homework assignment grade for bringing this back signed by January16th. An e-mail copy may be requested at .

Structure and Transformation of Matter

07-PS1-2 Analyze and interpret data on the properties of substances before and after the substances interact to determine if a chemical reaction has occurred.

1-2a I can identify properties of substances (before and after a reaction).

1-2b I can identify/collect physical characteristics and chemical properties

of pure substances.

1-2c I can explain and identify the requirements to determine if a

chemical reaction has taken place.

1-2d I can observe substances before and after they are mixed to

determine if a chemical reaction took place.

07-PS1-5 Develop and use a model to describe how the total number of atoms does not change in a chemical reaction and thus mass is conserved.

1-5a I can describe an atom.

1-5b I can state the law of conservation of mass.

1-5c I can evaluate the evidence of two mixed substances to determine if

a chemical reaction occurred.

1-5d I can create a model to demonstrate the Law of Conservation of

Mass.

1-5e I can observe the mass of products and reactants to prove mass is

conserved in a chemical reaction.

Matter Unit – main concepts outlined

A.  Matter

1.  Define -anything that has mass (weight here on Earth) and volume (takes up space)

2.  States (or phases)of matter –

a)  There are 4 states of matter

  1. Solid – atoms are locked close together in a fix position
  2. Liquid – atoms are more loosely attached and may move around allowing it to flow.
  3. Gas – atoms spread apart to fill any given volume
  4. Plasma - atoms are spread apart and electrically charged

b)  Changing state of matter -can be changed by adding or subtracting heat

  1. Melting – add heat to make solidàliquid
  2. Freezing – subtract heat to make liquid à solid
  3. Vaporize (boil or evaporate) – add heat, liquid à gas
  4. Condense –subtract heat to make gas àliquid
  5. Sublimate – rare – when heat causes solid àgas

c)  Unique melting and boiling points for different matter – not all can be changed within the temperature range that exists here on Earth.

  1. Water has a melting point of 32 °F/0 °C and boiling point of 212 °F/100 °C
  2. Iron has a melting point of 2800 °F /1538 °C and boiling point of 5182 °F/2861 °C
  3. Chocolate has an approx. melting point of 91 °F/32 °C and it burns at high temps (like most organic matter)
  4. Dry ice will sublimate at -109.3 °F /-78.5 °C

3.  Properties of matter

a)  Physical Property– any property that can be observed with your senses or measured with a tool without changing the matter into something new.

  1. Color
  2. State of matter at room temperature (solid, liquid, gas)
  3. Conductivity- lets electricity flow through it
  4. Elasticity – stretches and returns to original shape
  5. Malleability – how easily it can be bent/shaped
  6. Metallic or non-metallic
  7. Melting point or boiling point
  8. pH – acid or base
  9. Solubility – if it dissolves in a liquid
  10. Density – mass divided by volume, how heavy it is per size piece

b)  Chemical Property - any property that describes what a substance does during a chemical change (how it will react)

  1. Explosive
  2. Reacts with water
  3. oxidizes - reacts with air
  4. Corrosive –can “eat away” a substance
  5. Flammable – burns (organic matter – carbon based)

4.  Changes in matter

a)  Physical changes – the way a substance looks changes but its structure at the molecule level has not changed.

  1. Folding, ripping, or tearing an item like paper
  2. Re-shaping an item like clay
  3. Freezing or melting a substance like water

b)  Chemical changes - can only be observed if a chemical reaction is happening. It is often NOT reversible. The chemical formula changes –it gets new properties

  1. Burning organic matter like paper or wood
  2. Cooking - Baking a cake or cooking meat
  3. Rusting of iron

c)  Signs of a chemical change – if it does these on its own

  1. Change in color
  2. Change in temperature
  3. Produce a gas (or a solid)
  4. Have a new odor

5.  Structure of Matter

a)  Atom – the smallest complete unit of matter. All matter is made of atoms. There are 116 different atoms that make up the elements – they are all on the periodic table.

  1. Atomic structure – each atom is made up of 3 parts in 2 areas

Þ  Protons (+) in nucleus

Þ  Neutrons (0) in nucleus

Þ  Electrons (-) in electron cloud

  1. Atomic Number –the number of protons in an atom. Each element has its own unique atomic number
  2. Atomic Mass –is the weight of the atom determined by adding the number or protons with the number of neutrons (electrons are too small to count)
  3. Elements are grouped on the periodic table by chemical and physical properties
  4. Isotopes are atoms of the same element with different numbers of neutrons ( example -C14 and C12)
  5. Atoms will gain, loose, or share electrons to make molecules

b)  Molecule – when 2 or more atoms are chemically stuck together they form a new substance with it’s own unique physical and chemical properties.

  1. Chemical formula – the unique combination of element symbols and numbers to make a molecule of a compound
  2. H2O – 2 Hydrogen and 1 Oxygen atom makes water
  3. If they share electrons it is a covalent bond
  4. If one atom “gives” electrons to another and the opposite charges hold them together it is an ionic bond

c)  Mixture - 2 or more elements and/or compounds that are physically in the same area but not chemically bonded.

  1. Heterogeneous – not mixed at molecular level – can usually be separated by physical properties
  2. Homogeneous (solution) – mixed evenly at molecular level so that individual parts can not been seen – can be separated but it is harder to do.

Þ  Liquid-liquid vinegar

Þ  Liquid-solid salt water

Þ  Liquid-gas carbonated water

Þ  Solid-solid brass

Þ  Gas-gas air

6.  Chemical equations – a way to represent a chemical change

a)  Conservation of Matter – matter can not be created nor destroyed, only changed (must start and end with exact same number of atoms)

b)  The elements or compounds on the left side are called the reactants – they are what you start with

c)  The arrow represents chemical change

d)  The elements or compounds on the right side of the arrow are the products – they are what you end up with

e)  There are 4 main type of chemical reactions

i.  Synthesis (composition): two or more elements or compounds may combine to form a more complex compound A + X à AX

ii.  Decomposition: A single compound breaks down into its component parts or simpler compounds

AX à A + X

iii.  Replacement: a more active element takes the place of another element in a compound and sets the less active one free.

A + BX → AX + B

or AX + Y → AY + X

iv.  Ionic (double replacement): occurs between ions in aqueous solution. A reaction will occur when a pair of ions come together to produce at least one of the following: a precipitate, a gas or water (or some other non-ionized substance)

AX + BY → AY + BX

I have looked through the unit outline:

Parent/guardian: ______

Student: ______

Once I have seen this signed the student may place it in their binder or take it back home

Reaction types

Synthesis

1.  Metal + oxygen → metal oxide

EX. 2Mg(s) + O2(g) → 2MgO(s)

1.  Metal + nonmetal → salt

EX. 2 Na(s) + Cl2(g) → 2NaCl(s)

1.  Nonmetallic oxide + water → acid

EX. CO2(g) + H2O(l) → ; H2CO3(aq)

Decomposition

1.  Metallic carbonates, when heated, form metallic oxides and CO2(g).

EX. CaCO3(s) → CaO(s) + CO2(g)

1.  Some acids, when heated, decompose into nonmetallic oxides and water.

EX. H2SO4 → H2O(l) + SO3(g)

1.  Some decomposition reactions are produced by electricity.

EX. 2H2O(l) → 2H2(g) + O2(g)

Replacement

1.  Replacement of a metal in a compound by a more active metal.

EX. Fe(s) + CuSO4(aq) → FeSO4(aq) + Cu(s)

1.  Replacement of hydrogen in water by an active metal.

EX. 2Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g)

EX. Mg(s) + H2O(g) → MgO(s) + H2(g)

1.  Replacement of hydrogen in acids by active metals.

EX. Zn(s) + 2HCl(aq) → ZnCl2(aq) + H2(g)

Ionic (double replacement)

1.  Formation of precipitate.

EX. NaCl (aq) + AgNO3(aq) → NaNO3(aq) + AgCl(s)