Grade 10 Science reactions test

What is a qualitative observation

Senses are used to describe for example (be specific)

• texture

• colour

• odor

• shape

• sound

what is a quantitative observation

involves measurement (value + unit) uses an instrument involves precision and accuracy

What is a physical property

Observed without senses and can also be measured; it is a property of a substance that can be observed without changing the substance

What is a chemical property

A property of a substance that can only be observed as the substances change into another substance

What is a chemical change

The original elements & or compounds are changed into a new substance with new chemical and physical properties. A chemical change may be or may not be reversible

What is a physical change

The substance remains the same substance only the appearance changes.

• A physical. change does not alter the composition of matter

What are the indicators of a chemical change?

• Emission of light

• Unexpected colour change

• Fizzing/Bubbling

• Production of heat

• Percipitate formed

• Change in quantity

• Change in Odour

• Formation of sound

Physical or chemical change: Dry ice sublimating from a solid into a gas

Physical change

Physical or chemical change: the moisture form your breathe (a gas) condensing onto a cold glass window

Physical change

Physical or chemical change: an open bottle of soda bubbling

Physical change because carbon dioxide gas (CO2) is being released

What is a synthesis chemical reaction

• When two simple elements/compounds combine to produce one complex compound

What is the formula for synthesis chemical reaction

A + B ➟ AB

What is a decomposition chemical reaction

• When a complex compound breaks down into two simple elements/compounds

What is the formula for a decomposition chemical reaction

AB ➟ A + B

What is a single displacement chemical reaction

• Takes place between two anions (non-metals) or two anions (metals) where one element replaces another in a compound

What is the formula for a single displacement chemical reaction

M + XY ➟ X + MY (where M and X are metals)

Nm + XY ➟ Y + XNm (where Nm and Y are non-metals)

What is a double displacement chemical reaction

Anions (non-metals) and Cations (metals) from two different compounds exchange places

What is the formula for a double displacement chemical reations

AB + DC ➟ AD +BC

What is a acid-base neutralization chemical reaction

• Acid and base turn into a salt (ionic compound) and water (H2O)

What is the formula for an acid base netralization chemical reaction

HNm (aq) + MOH (aq) ➟ MNm (aq) +H2O (l)

What is a combustion chemical reaction

• The rapid release of a substance with oxygen to produce oxides and energy

What is the formula for combustion with hydrocarbons

CxHy + O2 ➟ CO2 + H2O + energy

• (where x and y is a subscript representing a certain amount of carbon and hydrogen)

• Complete formula

What is the formula for an incomplete combustion chemical reaction and what does incomplete mean in the chemical reaction

• Incomplete means not enough O2 to completely react with the hydrocarbons

Formula is CxHy (g) + O2 (g) ➟ CO2 (g) + H2O (l) + CO (g) + C (s)

CO = carbon monoxide gas

C = carbon soot which is a solid

What are general characteristics of a single displacement reaction

• Usually takes place in aqueous solutions

• Useful for comparing reactivity of metals or halogens

• Uses activity series of metals or halogens

(single displacement) Metal displaces another metal: formula and requirement

• Metal A must be more reactive than metal B to displace it (higher on the activity series)

• Formula: M + XY ➟ X + MY (where M and X are metals)

(single displacement) Metal displaces hydrogen form an acid: formula and requirement

• Metal must be more reactive than hydrogen from an acid to displace it (higher on the activity series)

• Formula: M (s) + HNM (aq) ➟ H2 (g) + MNM (aq)

• Result is hydrogen gas (H2) and an ionic compound that is aqueous

(single displacement) Metal displaces hydrogen from water: formula and requirement

• Metal must be more reactive than hydrogen from cold water to displace it (higher on the activity series)

• M (s) + H2O (l) ➟ H2 (g) + MOH (aq)

• Always forms hydrogen gas and metal hydroxide that is aqueous

• Turn H2O into H-OH

Guidelines when a metal displaces hydrogen

• Treat H as a metal

• Treat acids as ionic compounds ➟ e.g HCl ➟ H-Cl

• Treat water as ionic compounds ➟ H2O ➟ H-OH

What elements on the activity series of metals displaces hydrogen from cold water

• Any element above magnesium on the actvity series of metals

What elements on the activity series of metals displace hydrogen form acids

Any acids above lead (including lead)

(single displacement) Non-metal displaces another non-metal: formula and requirement

• Non-metal X must be more reactive than non-metal Y to displace it

• Formula: X2 (aq) + MY (aq) ➟ Y2 (state varies) + MX (aq)

• Uses activity series of halogens

• non-metal elements are always diatomic

• Metal and non metal are always an ionic compound (salt)

Double displacement to form a precipitate: formula, requirement and precipitate meaning

• A precipitate is a solid formed in a chemical reaction that takes place in a solution

• Use solubility chart to find out if the compound formed is soluble (aq) or insoluble (s)

• Formula: AB (aq) + CD (aq) ➟ AD (s) + CB (aq)

• for this reaction to occur you must have one precipitate (solid compound) and one soluble compound (aq compound)

Double displacement to produce water (neutralization): Formula and requirement

• An acid and base is required to react and form a salt (ionic compound) and water

• Formula HNm (aq) or HNmO (aq) + MOH (aq0 ➟ MNm (aq) + H2O (l)

Double displacement to produce CO2 (carbon dioxide) (watch for H2CO3)

Word formula: Metal carbonate (aq) + Hydroacid (aq) ➟ Ionic compound (aq) + H2CO3 (aq) ↳ H2O (l) + CO2 (g)

Chemical formula: MCO3 (aq) + HY (aq) + MNm + H2CO3 ↳ H2O + CO2

Double displacement to produce SO2 (sulfur dioxide) (watch for H2SO3)

Word formula: Metal Sulfite (aq) + hydroacid (aq) ➟ Ionic compound (aq) + H2SO3 ↳ H2O (l) + SO2 (g)

Chemical formula: MSO3 (aq) + HY (aq) ➟ MNm (aq) + H2SO3 ↳ H2O (l) + SO2 (g)

Double displacement to produce NH3 (Ammonia) (watch for NH4OH))

Word formula: Ammonium non-metal ionic compound (aq) + Metal hydroxide base (aq) ➟ Ionic compound (aq) + Ammonium hydroxide (aq) ↳ NH3 (g) + H2O (l)

Chemical formula: NH4Nm (aq) + MOH (aq) ➟ MNm (aq) + NH4OH (aq) ↳ NH3 (g) + H2O (l)

Double displacement to produce H2S (hydrogen sulfide)

Word formula: Metal sulfide (aq) + hydroacid (aq) ➟ Ionic compound (aq) + Hydro sulfide (g)

Chemical formula: MS (aq) + HNm (aq) ➟ MNm + H2S

Double displacement to produce H2 (hydrogen gas)

Word formula: Metal hydride (s) + water (l) ➟ Metal hydroxide (aq) + Hydrogen gas (g)

Chemical formula: MH (s) + H2O (l) ➟ MOH (aq) + H2 (g)

why does H2 gas production act like a single displacement question

• Pure metal hydrides act like a single element. They force hydrogen ions completely out of water to form pure, elemental H2 gas

(Synthesis reaction) element + element ➟ compound: formula

A + B ➟ AB

(Synthesis reaction) Production of a base: formula

Word formula: MOxide (s) + water (l) ➟ base (metal hydroxide) (aq)

Chemical formula: MO (s) + H2O (l) ➟ MOH (aq)

(Synthesis reaction) Production of an acid (oxyacid): formula

Word formula: NmOxide (g) + water (l) ➟ acid (aq)

Chemical formula: NmO (g) + H2O (l) ➟ HNmO (aq)

(Synthesis reaction) Production of a salt (ionic compound): formula

Word formula: NmOxide (g) + MOxide (s) ➟ Salt (s)(ionic compound)

Chemical formula: NmO (g) + MO (s) ➟ MnmO (s)

(decomposition reaction) compound ➟ element + element : formula

AB ➟ A + B

(Decomposition reactions) decomposition of bases: formula

Word formula: Base (aq) ➟ MOxide (s) + water (l)

Chemical formula: MOH (aq) ➟ MO (s) + H2O (l)

(Decomposition reactions) decomposition of acids (oxyacids): formula

Word formula: Acid (aq) ➟ NmOxide (g) + water (l)

Chemical formula: HNmO (aq) + NmO (g) + H2O 9l)

( Decomposition reaction) decomposition of salt (formula)

Word formula: Salt ➟ MOxide + NmOxide

Chemical formula: MNmO (s) ➟ MO (s) + NmO (g)

What is the chemical composition and state of salt?

• General Formula: MX (Metal + Non-Metal / Polyatomic Ion)

• General State: Solid (s) in pure form; Aqueous (aq) if soluble in water

• Note: Formed from neutralization reactions or precipitation reactions

What is the chemical composition and state of Oxides

• General Formula: NMO (Non-Metal + Oxygen)

• General State: Gas (g) at room temperature

• Chemical Nature: Reacts with water to form oxyacids (e.g., SO3 + H2O -> H2SO4)

What is the chemical composition and state of Oxyacids

• General Formula: H(Poly) or HXO (Hydrogen + Polyatomic ion containing Oxygen)

• General State: Aqueous (aq) when dissolved in water

• Note: Examples include HNO3(aq) and H2SO4(aq)

What is the chemical composition and state of hydroacids

• General Formula: HX (Hydrogen + Non-Metal)

• General State: Aqueous (aq) when dissolved in water

• Note: Examples include HCl(aq) and HBr(aq)

What is the chemical composition and state of base

• General Formula: MOH (Metal + Hydroxide ion)

• General State: Aqueous (aq) or Solid (s) before dissolving

What is the chemical composition and state of hydrocarbons

• General Formula: CxHy (Carbon + Hydrogen only)

• General State: Gas (g) for small molecules (1-4 carbons); Liquid (l) for medium molecules (5-17 carbons); Solid (s) for large molecules (18+ carbons)

What is the chemical composition and state of Metal oxides

• General Formula: MO (Metal + Oxygen)

• General State: Solid (s) at room temperature

• Chemical Nature: Basic oxides (form bases when dissolved in water)

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What is the chemical composition and state of non metal oxides

• General Formula: NMO (Non-Metal + Oxygen)

• General State: Gas (g) at room temperature

• Note: A few exceptions form solids (like SiO2/sand) or liquids (like H2O)

What is an ionic compound made up of

A cation (positive ion) and an anion (negative anion) bonded together with an ionic bond

Is water polar or non polar bond

water is a polar covalent bond

Definition of polar compounds

Molecules where electrons are shared unequally between atoms because one side of the molecule develops a partial positive and negative charge

Definition of non polar compounds

Molecules are shared evenly between atoms resulting in no charge seperation

What does a delta plus show

Shows that a molecule is slightly positive

What does a delta negative show

show that a molecule is slightly negative

Rule for solubility

Like dissolves like polar dissolves polar non polar dissolves non polar

Dissociation process

• What it is: The separation of an existing ionic compound into its individual mobile ions when dissolved in water.

• What breaks: Ionic bonds break as water molecules pull the ions apart.

In dissociation equations substances in the aqueous state are represented as

Ions shows charge as well

In dissociation questions substances in the solid liquid or gas state are represented as

Molecular compounds no charge is added

What does a dissociation equation show?

1. Physical states changing from solid (s) to mobile aqueous ions (aq).

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2. Conservation of mass (balanced elements on both sides).

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3. Conservation of charge (the total net charge on the product side must equal zero).

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4. The ratio of ions produced (e.g., CaCl2 produces twice as many Cl- ions as Ca2+ ions).

5 polyatomic ions and their charges

• Nitrate: NO3 with a 1- charge (NO3-)

• Chlorate: ClO3 with a 1- charge (ClO3-)

• Sulfate: SO4 with a 2- charge (SO4^2-)

• Carbonate: CO3 with a 2- charge (CO3^2-)

• Phosphate: PO4 with a 3- charge (PO4^3-)

What is a Catalyst? (and heat)

• A chemical substance (element or compound) that speeds up a reaction without being used up by lowering the activation energy.

• If heat is needed you must put a triangle above the yield sign to symbolize that

• All catalyst are written on top of the yield sign

What is an Indicator

Meaning: A special substance that reveals the presence of an acid or a base by changing its colour.