Download - Law of Conservation of Mass Essential Lab
Law of Conservation of Mass Essential Lab
Catalyst1. Classify the following as an element,
compound or mixture:a) Baking sodab) Carbon
2. Classify each of the following as a homogeneous or heterogeneous mixture
a) Mouthwashb) Ice cubes in water
SWBAT apply the law of conservation of mass to chemical and physical changes
Agenda• We do: Lab setup (10 min)• You do: LoCM Essential Lab (60
min)• I do: Law of Conservation of Mass
Mini lesson (10 min)• You do: data analysis and
conclusion (10 min)
HOW IS MASS AFFECTED DURING A CHEMICAL AND PHYSICAL CHANGE?
LET’S FIND OUT!
Essential Lab• You will be performing physical and
chemical changes on different substances and measuring the mass before and after the change– Formation of a precipitate– Crushing smarties– Melting ice– Baking soda and vinegar– Dissolving sugar– Dissolving Alka-seltzer
Conservation of Mass Lab• You will need to write a complete lab report, with
all of the components from the ETO lab template– Cover page– Title– Introduction– Problem statement– Hypothesis– Materials – Procedures (1-2 sentences for each table)– Variables– Data – Data analysis– Conclusion
Lab Setup• Leave a space in your notebook for the
cover page, title and introduction• Write down the problem statement,
hypothesis, materials and variable– Problem Statement: How is the mass of
matter affected if it undergoes a physical or a chemical change?
– Hypothesis: How do you think the mass of the matter will be affected after the change? Will it increase, decrease or stay the same? WHY?
– Variables: IV, DV, Control, Constant
Lab Data and Calculations• Data tables (6 total) = ‘change in’
• Particle level representation (6 total)• Is this a physical or a chemical change?• How would particles look with a physical or
a chemical change?
You have 8 minutes at each station• USE YOUR TIME WISELY• Lab group roles
• Project director = makes sure group is on task and on time
• Technical manager = performs all the measurements on the balance
• Materials manager = organizes and cleans materials before moving to the next station
• Safety director = keeps track of time, assists materials and project director
Lab Expectations• You will clean the materials when you are
asked to do so• You will rotate to the next station when you are
asked to do so• You will not leave your station unless you are
the technical director• You will not talk to other lab groups• You will not prevent other groups from going to
a station because you did not use time wisely and did not finish
LABS ARE A PRIVLEDGE• If you are not following lab
expectations you will be given a data sheet and asked to complete the lab from your seat.
WHAT WERE YOUR RESULTS? WAS YOUR HYPOTHESIS SUPPORTED?
Law of Conservation of Mass
Mass cannot be created or destroyed, it can only be converted
State the Law. Equation
In a Picture Common Misconception
In any physical or chemical reaction, the
total mass is conserved or does not
change.
massreactants= massproducts
Mass does not change even if the
substance changes to a new phase.
Law of Conservation of Mass
Other ways to say “conserved”• Saved• Keep• What goes in must come out• Reactants equal products • Remains• massreactants= massproducts
Data Analysis and Conclusion• Make sure you have a data table
and particle level representations for ALL six parts
• Answer the ‘DATA ANALYSIS’ part with complete sentences
• Answer all 7 conclusion questions (minimum 3 paragraphs)
• Complete lab report as homework – due next class
Extra ProblemMagnesium reacts with oxygen to produce magnesium oxide. If 2.4g of magnesium reacts to make 2.9g of
magnesium oxide, how many grams of oxygen react?
Extra Problem• Donald does a reaction in which he mixes 40
grams of sodium hydroxide with 32 grams of another chemical. After the reaction has completed, he is left with a precipitate that has a mass of 18 grams. How much gas was released in this reaction?
Another way to say mass is conserved is to say that the mass of the reactants equals the
mass of the prodcuts
Extra Problem50 grams of sodium reacts with chlorine to form 126 grams of salt. How many grams of
chlorine reacted?