Catalyst – December 88-(2x40.5) 2009

Monday Mystery Element!

1. It is very strong and very light.

2. It is used in surgical pins and artificial hips.

3. 10,000 pounds of this is used when making a Boeing 747.

Weekly Goal!

Catalyst – December 88-(2x40.5) 2009Monday Mystery

Element!1. It is very strong and

very light.2. It is used in surgical

pins and artificial hips.

3. 10,000 pounds of this is used when making a Boeing 747. TITANIUM

Today’s Agenda Catalyst Endo/Exo Lingo! Intro to Acids and Bases, pH,

and Indicators Lab Time More Learnin! Exit Question

Today’s Objectives SWBAT describe endothermic

and exothermic reactions. SWBAT classify substances as

acidic, basic, or neutral using indicators.

What happened during the 1st reaction?H3C6H5O7(aq) + NaHCO3(s)

CO2(g) + H2O(l) + Na3C6H5O7(aq)

That’s right! It got…ICE COLD!!!

What happened during the 2nd reaction?

Mg(s) + HCl(aq) H2(g) + MgCl2(aq)

That’s right! It got…SPICY HOT!!!

Why did the temperature change?!? Because ENERGY is in the mix,

y’all!Key Point #1: Every bond has

energy holding it together. Breaking a bond requires energy. Forming new bonds releases energy.Unit for energy: kilojoules (kJ)

Endothermic ReactionsKey Point #2: If the total heat taken in by a reaction is more than the heat released, it is called an endothermic reaction.

REACTANTSPRODUCTS

Net energy

is absorbe

d!

Exothermic ReactionsKey Point #3: If the total heat released by a reaction is more than the heat taken in, it is called an exothermic reaction.

REACTANTSPRODUCTS

Net energy

is released

!

Which of these is endo/exo???

1. 2 HCl + 185 kJ H2 + Cl2 2. 4 NH3 + 5 O2 4 NO + 6 H2O + 1169 kJ

3. Cu + Cl2 CuCl2 + 220.1 kJ

4. H2O + C + 132 kJ CO2 + 2H2

Some Qu-Qu-Questions to ponderThe combustion of the

hydrocarbon glucose (C6H12O6) produces carbon dioxide, water, and releases 2830 kJ.

Exo or Endo???

Some Qu-Qu-Questions to ponderAfter absorbing 66.4 kJ of energy,

1 mole of nitrogen gas and 2 moles of oxygen gas react to form 2 moles of nitrogen monoxide.

Exo or Endo???

WHY DO WE NEEDTO KNOW ABOUT

ACIDS AND BASES?

Without ACIDS…You could NOT digest

food!Cold drinks would NOT

be the same!

Without BASES…You could NOT get your body…or house…or car

clean!You could NOT cure an

upset stomach!

The downside of some ACIDS…

Acid rain destroys buildings and statues

Acid in drinks damages tooth enamel

Heart burn hurts!

The downside of BASES…

Bases slime your skin off.

PROPERTIES

OF…..

Key Point #1: Properties of acids:

CorrosiveSour taste pH less than 7

PROPERTIES

Key Point #2: Properties of bases:

Soapy/slippery feel Bitter tastepH more than 7

PROPERTIES

How do we tell if a substance is an acid or a base?Key Point #3: Scientists use INDICATORS to identify acids, bases, and neutral solutions.

An indicator is a substance that turns a certain color in the presence of an acid, base, or neutral solution.

A neutral solution is not acidic or basic.

Litmus! Litmus might sound like a terrible

disease, but this is not true! Litmus PAPER is a type of indicator used

to identify acids, bases, and neutral solutions.

Lab Time! In this lab, you will be using the red and

blue litmus paper to classify unknown solutions as acids, bases, or neutral solutions.

Place each color of litmus paper into each solution and record results in data table.

Hint for Post-Investigation Questions: Lemon juice is an ACID Ammonia is a BASE

Red and Blue Litmus Paper

Red litmus paper turns blue in the presence of a base (doesn’t change color in acid)

Blue litmus paper turns pink/red in the presence of an acid (doesn’t change color in base)

pH ScaleKey Point #4: pH is a scale used to identify acids, bases, and neutral solutions. It ranges from 1-14. Acids have a pH less than 7 Bases have a pH more than 7

Exit Question1. Describe the difference between

an endothermic reaction and an exothermic reaction.

2. If you have a solution that has a pH of 4.0, what color will it turn litmus paper? Is this solution an acid or a base?

Please leave lab paper in folder!

Exit Question1. If you have a solution that has

a pH of 4.0, what color will it turn litmus paper? Is this solution an acid or a base?Please leave lab paper in

folder!