9.1Law$of$Conservationof$Mass$ $ $ $ Date:$ · 9.2 Writing Balanced Equations Part 1 Date: Warm up: Study Notes/Questions Writing and Balancing Chemical Equations Chemical equations

9.1 Law of Conservation of Mass Date:

Warm up:

Study Notes/Questions Describing Chemical Reactions

_________________________ manufacture things used daily

E.g.

Chemical reactions

involve ___________________________ _________________substances are formed collisions cause bonds to break and ___________________________________ Chemical equations uses chemical formulas describes the chemicals that react______________________ and those that are produced _______________________

Law of Conservation of Mass

In a “closed system” (nothing is allowed in or out)

Chemical “equation” means something must be __________________________

Total # of ____________________is the same in reactants and ______________

We say ____________ are CONSERVED and ___________ is CONSERVED (stay the same)

Summary: (two to three sentences summarizing this section)

Self-‐Reflection Questions:

1. Describe one thing that you knew about this topic before today.

2. Describe one thing you learned about this topic today.

9.1 Part 1 Activity

1. What is the main difference between a physical change and a chemical change? 2. For each of the following, state whether it is a physical change or a chemical change. Give reasons for each answer. (a) freezing water to form an ice cube (b) burning toast (c) placing a nail in water and allowing it to rust (d) pouring concrete onto a driveway and allowing it to set (e) pouring molten silver into a mould to solidify and make jewellery (f) composting leaves by allowing them to rot and decay in a box (g) shredding leaves with a lawn mower 3. Hydrogen gas (burns extremely fast) and oxygen gas (supports burning) can be combined to make

water, which can put out fires. Explain why water is so different from its components. 4. What is a chemical equation? 5. Use words to describe the following chemical equations.

(a) S + O2 → SO2

(b) 2 SO2 + O2 → 2 SO3

(c) N2 + 3 H2 → 2 NH3

9.2 Writing Balanced Equations Part 1 Date:

Warm up:

Study Notes/Questions Writing and Balancing Chemical Equations

Chemical equations are used to describe __________________________

_________________– uses chemical names (words) to describe a reaction

__________________ – uses chemical formulas to  describe a reaction

To show that mass/atoms are conserved we must count all atoms

Coefficients - give the number of molecules of each compound or element

Subscripts – give the number of atoms of each element.

Total atoms shown: ___ hydrogen, ___ oxygen

For formulas with brackets, the subscript outside multiplies everything inside


Self-Reflection

Questions:

1. Describe one thing that you knew about this

topic before today.

2. Describe one thing you learned about this

topic today.

Counting Atoms and Molecules Analyze each chemical formula and indicate how many particles of each type are represented

1. C3H8

How many molecules of C3H8 ? ____________

How many atoms of C ? __________________

How many atoms of H ? ___________________

2. 3 KClO3

How many molecules of KClO3? ____________

How many molecules of K? _______________

How many atoms of Cl ? __________________

How many atoms of O? ___________________

3. 2 (NH4)2SO4

How many atoms of (NH4)2SO4? ___________

How many molecules of N? ______________

How many atoms of H ? __________________

How many atoms of S? ___________________


4. 2 C8H17OH

How many molecules of C8H17OH? ____________

How many atoms of C ? __________________



5. 4 Ca(H2PO4)2

How many molecules of Ca(H2PO4)2 ? ________

How many atoms of Ca ? __________________


How many molecules of P? ________________

How many molecules of O? _______________

9.2 Writing Balanced Equations Part 2 Date:

Warm up:

1. Determine the number of H atoms in 3H2O.

2. Determine the number of molecules in 4Na2S.

3. Determine the number of O atoms in 3Ca(H2PO4)2

Study Notes/Questions Writing and Balancing Chemical Equations

When the number of atoms of ________________________ is the same as the number of atoms ____________________________ the equation is ______________________.

2 H2O → 2 H2 + O2

H atoms __ O atoms __ H atoms & __ O atoms

Balance the following Chemical Reactions

__ Sn + __ O2 → __ SnO4

__ MgCl2 → __ Mg + __ Cl2

__ KNO3 → __ KNO2 + __ O2

.

9.2 Writing Balanced Equations Part 2

__Ca3(PO4)2 + __ H2SO4 → __ CaSO4 + __ Ca(H2PO4)2


Self-Reflection

Questions:

1. Describe one thing that you knew about this

topic before today.

2. Describe one thing you learned about this

topic today.

9.2 Activity: Balance the following chemical equations

1) ____ CH4 + ____ O2 → ____ CO2 + ____ H2O

2) ___ Na + ___ Cl2 → ____ NaCl

3) ____ Al + ____ O2 → ____ Al2O3

4) ____ N2 + ____ H2 → ____ NH3

5) ____ CO + ____ H2 → ____ C8H18 + ____ H2O

6) ____FeO3 + ____ CO → ____ Fe + ____ CO2

7) ____ H2SO4+ ____Pb(OH)4 → ____ Pb(SO4)2 + ____ H2O

8) ____ Al + ____ HCl → ____ AlCl3 + ____ H2

9) ____ Ca3(PO4)2 + ____ H2SO4 → ____ CaSO4 + ____ Ca(H2PO4)2

10) ____ H3PO4 + ____ HCl → ____ PCl5 + ____ H2O

9.3 Writing Balanced Equations Date:

Warm up:

Study Notes/Questions Types of Chemical Reactions

Six types: - Classified according to patterns of ______________________________

- Study pattern to predict products 1. ______________________ – combining 2 (or more) substances into 1  - can start with elements or compounds  - follow rules for writing formulas for product 2. _________________ – 1 substance breaking down into 2  (or more)  - products are elements or simpler compounds

3. ____________________________ – element reacts with compound - single element replaces one element in compound - metal replaces metal, non-metal replaces non-metal

4. _______________________________ – 2 compounds switch partners - 2 elements replace each other - new compounds will be ionic (+ ion/-ion) - follow formula writing rules

5. __________________________  (special kind of Double Replacement) H+ from acid and OH- from base neutralize to form H2O Acid + Base Salt + Water

6. _____________________ - burning of hydrocarbons - always requires oxygen gas - products are always CO2 and H2O

9.3 Writing Balanced Equations

Predicting Products Given the reactants for a reaction, you will be asked to  predict the products based on the patterns shown This requires an understanding of reaction types,  chemical formula writing, and balancing equations      





9.3 Predict the Reaction

Predict the type of reaction given the following reactants

1) K + O2 →

2) Pb(NO3)2 + Na2SO4→

3) C3H12 + O2 →

4) H2SO4 + NaOH →

5) Ca + Cl2 →

6) Li2S →

7) HgO →

8) HCl + Ca(OH)2 →

9) C3H7OH + O2 →

10) Al + S →

11) Al + CuSO4 →

9.3 Writing Balanced Equations Date:

Warm up:

Study Notes/Questions Predict the products from the given reaction and balance the equation

H2SO4 + NaOH C4H10 + O2 MgCl2 + AgNO3 Zinc + Hydrogen Chloride

9.3 Activity: Predicting Reaction Products

Predict the products and balance the equations for the following reactions:

1) ____ Na + ____ FeBr3 →

2) ___ Fe + ___ O2 →

3) ____ C2H4O2 + ____ O2 →

4) ____ PbSO4 + ____ AgNO3 →

5) ____ MgBr2 →

6) ____ K(MnO4)+ ____ ZnCl2 →

7) ____MnO2 + ____ Sn(OH)4 →

8) ____ O2 + ____ C5H12O2 →

9.3 Activity: Word Equations

Predict the products and balance the equations for the following reactions:

1) Aluminum bromide and chlorine gas react

2) Sodium phosphate and calcium chloride react

3) Potassium metal and chlorine gas

4) Aluminum and hydrochloric acid react

5) Calcium hydroxide and phosphoric acid react

6) Hydrogen gas and nitrogen monoxide react

9.4 Rates of Chemical Reactions Date:

Warm up:

Study Notes/Questions Rates of Chemical Reactions

Some chemical reactions are _____________ some are _______________________ For example The _________________________________________________ is the amount of reactant consumed per unit time or the amount of product formed per unit time. It is the __________________ of the reaction. When Zinc metal is combined with hydrogen chloride and 2 000 cm3 of hydrogen is produced in 12 minutes, what is the reaction rate?

__________________________________________ tells us that all matter is made  up of tiny, moving particles

Reaction rate is explained by the __________________________________,   which states that molecules must collide in order  to react.

Collisions must also be ___________________, which means that they must have __________________________ for a reaction to occur.

9.4 Rates of Chemical Reactions

Changing the frequency of effective collisions changes the reaction rate. Reaction rate can be increased by: 1. increasing the 2. increasing the 3. increasing the 4. adding a





3. What was the most interesting thing you learned this year about chemistry?

9.4 Part 1 Activity

1. What is meant by the term “rate of a chemical reaction”?

2. What variable always appears in any reaction rate calculation?

3. A sample of magnesium metal reacts with hydrochloric acid solution to produce magnesium chloride solution and hydrogen gas.

(a) Write a balanced chemical equation for this reaction. (b) If 0.80 g of magnesium reacts in 40.0 s, calculate the reaction rate. (c) If 20.0 mL of hydrogen gas are produced in 60.0 s, calculate the reaction rate.

4. The electrolysis (decomposition) of water produces hydrogen gas at the rate of 30.0 mL/min. (a) Write a balanced chemical equation for this reaction. (b) What volume of hydrogen gas can be produced in 4.5 min? (c) Based on your balanced equation, predict the rate of oxygen gas produced.

5. Name four factors that can affect the rate of a chemical reaction. How does the rate of a chemical reaction change in response to a change in each factor?

6. What is the fundamental premise of the collision theory?

7. What is necessary for a collision between reacting molecules to be effective?

8. Explain, using the collision theory, how each of the following factors affects reaction rate: (a) concentration of reactants (b) surface area of a solid reactant (c) temperature of the reactants (d) adding a catalyst

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9.1Law$of$Conservationof$Mass$ $ $ $ Date:$ · 9.2 Writing Balanced Equations Part 1 Date: Warm up: Study Notes/Questions Writing and Balancing Chemical Equations Chemical equations