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MASS LOSS METHOD
Variables :
Kept constant:
-Mass if shell
-Volume of HCl

Independent:
Type of shell

Dependent:
Change in mass

Apparatus
- Balance
- 3 Beaker
- Measuring cylinder

Quantity to be measured:
Change in mass of the contents of the beaker

Data collected:
Loss in mass in grams using a electronic balance.

Data process:
Calculate percentage of calcium carbonate in shell.

Steps:
1. Place beaker on the balance measure its mass.
2. Pour 60cm3 of HCl into the beaker, measure using measuring cylinder.
3. Weigh 5grams of Sample X using another balance.
4. Place Sample X in HCl, and record initial mass of beaker+contents.
5. Wait till there is no change in mass, and no more effervescence is produced
5.Record final mass. And calulate change in Mass. (Final-Initial)
6.Repeat steps 2-5 with sample Y.
7.The sample with more loss of mass is the Sample with a higher percentage of Calcium carbonate.

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Determining the percentage of CaCO3 in mussels.
1.Measure the initial mass of each mussel separately using an electronic balance (m1)
2.place both mussels into 2 small conical flasks separately
3.Measure the same volume of hydrochloric acid using a measuring cylinder for both flasks
4. Pour the same volume of  hydrochloric acid in excess into each flask
5. Wait for all the calcium carbonate to react with the acid by observing if effervescence stops.
6..After reaction is completed remove and dry the mussels with filter paper
7.Measure final mass of mussels using electronic balance(m2)
8.Use formula to determine percentage change mas  M!-M2/M1 x 100

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Gas syringe method.
Variables:
Constant: Initial mass of seashells, concentration of acid.
Independant: Type of seashell used
Dependant: Amount of CO2 collected.
Steps:
1) Place seashell A into a conical flask filled with excess hydrochloric acid.
2) Immediately connect conical flask to a gas syringe using a delivery tube.
3) Wait until no more bubbles are formed, indicating that all the calcium carbonate in the shell have reacted with the acid.
4) Measure and record amount of CO2 produced by reaction.
5) Repeat Steps 1-4 with seashell B
6) Compare amount of CO2 produced in both reactions. The reaction with the seashell that produced more CO2 contains a higher percentage of calcium carbonate and thus have a higher quality.

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method: percentage change in mass approach: add excess hydrochloric acid to the seashells and measure the percentage changed in mass using an electronic balance.

variables to be changed: the types of shell

variables to be kept constant: the amount of HCl added to the seashell and the temperature and relative humidity of the surrounding.

apparatus: 2 beakers, electronic balance, 2 conical flasks, 2 filter funnels and 2 pieces ofbfilter paper.

steps:
1. measure the initial mass of shell x and record it as m1. measure the mass of shell y and record it as m2.
2. add excess hydrochloric acid to shell x in a beaker and wait for the reaction to be completely finished.
3. filter the mixture and collect the residue and leave it to dry.
4. measure the mass of the residue and record it as m3.
5. calculate the percentage changed in mass for shell x using (m1-m3/m1) x 100%.
6. repeat steps 2-5 using shell y and compare the percentage changed in mass of the 2 shells.

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What are the essential apparatus?
-2 conical flasks
-2 different types of mussel shell, X and Y
-Electronic beam balance
-Dilute hydrochloric acid

Approach?
-Add mussel shells in different conical flasks and measure the change in mass of the contents (mussel shells & HCl)

Changed variables: Type of mussel shell

Constant variables:
-environment (e.g. wind)
-initial mass of shell
-volume of HCl acid

Measured variable: changed in mass of the mussel shells

1. Record the initial mass of both shells
2. Measure the final mass of both shells after the acid is added to the mussel shells. (Ensure that the acid reaction had completed)
3. Calculate the change in percentage of mussel shells by taking the initial mass of the mussel shells and subtract it by the final mass. Then, multiply it by 100%. (processed data)

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Approach:
React the shells with excess hydrochloric acid and calculate the percentage change in mass of both seashells.

Variables:
Independent- The type of shell
Constant- Type & volume of acid, mass of beaker.

Apparatus:
-Electronic balance
-Beakers
-Measuring cylinder

Steps:
1.Wash and dry the seashells
2.Place the shells into two seperate beakers.
3.Measure and record the intial mass of the shell in the beakers using an electronic balance.
4.Add excess hydrochloric acid into both of the seashell samples using a measuring cylinder.
5.Wait for the reaction to end by the absence of effervescence.
6.Filter the mixture and collect the residue of seashell samples.
7.Measure the mass of the residue separately using an electronic balance.
8.Repeat steps 3-7 and find the average mass for both seashells
9.Record the final mass and calculate the percentage change in mass of both seashells.

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Changed Variable:
Mussel shall.

Measured:
Mass of shell before and after experiment(Mass difference)

Constant Variables:
Type of Acid Used.
Volume of acid used.

Procedure:
1)Weigh Shell X using an electronic balance and label it w1.
2) Measure 100cm^3 of sulfuric acid using a measuring cylinder and pour it into a beaker.
3) Add Shell X to the beaker and wait for the reaction to be complete(when effervescence stops)
4)Weigh shell X again with the electronic balance and label it w2.
5)Calculate percentage change in mass of Shell X using the formula ((w2-w1)/w1)*100% to obtain the percentage of CaCO3 present in the shell.
6) Repeat Steps 1-5 using Shell Y.
7) Compare the 2 percentages and determine which shell has a higher percentage of Calcium Carbonate.

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Variables changed: Type of shell
Variables constant: Amount of HCl
What we measure: Difference in initial mass of seashell and final mass of seashell

Approach:
1) Measure initial mass of both seashell X and Y
2) Place both shells into 2 separate beakers
3) Add excess amount of HCl into both beakers
4) Allow the reaction to be completed
5) When effervescence and decrease in size of the seashell stops, the reaction has stopped
6)Remove the shells from the acid and dry them with a cloth
7) Measure the mass of the shells at the end
8) Calculate the difference in mass from the start
9) The shell with the higher change in mass has a higher CaCO3 percentage

Apparatus:
1 Electronic Balance
2 Beakers
Cloth (For drying)

Materials:
2 Different shells (X and Y)
Hydrochloric acid

Quantities
Mass of shell at start and end

Data Processing
Initial mass - Final mass = Difference in mass

# data[].attributes.headline
Determining the percentage of CaCO3 ( in seashells

# data[].attributes.subject
Determining the percentage of CaCO3 ( in seashells

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Joel and Serene

APPROACH
Add HCl (aq) to each shell and collect and measure volume of gas produce with gas syringe.

VARIABLES
Changed:
- Shell used
Constant:
- Volume of HCl (aq) used
- Surrounding temperature
- Container used
Measured:
- Volume of CO2 (g) produced

PROCEDURE
1. Add excess HCl (aq) of the same volume to each conical flask labeled X and Y.

2. Drop Shell X into flask X and Shell Y into flask Y.

3. Attach delivery tube with gas syringe onto each flask as soon as the shell is added and collect CO2 (g) produced.

4. When effervescence stops, measure the volume of CO2 (g) in each gas syringe.

COLLECTING DATA
Record the volume of CO2 (g) produced by Shell X as V1 and Y as V2.

PROCESSING DATA
Compare the value of V1 and V2. The higher value of CO2 (g) produced in the setup has the shell with the higher percentage of CaCO3 (s).

# data[].attributes.headline
Determine the shell with the highest percentage of Calcium Carbonate. Athuf & Cheyanne

# data[].attributes.subject
Determine the shell with the highest percentage of Calcium Carbonate. Athuf & Cheyanne

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approach: mass loss method
variables:
-KepConstant: vol of acid used and mass of shell used
-Change: percentage of calcium carbonate in each shell

1. Measure 500ml of hydrochloric acid using a measuring cylinder and  pour it into two beakers with 250 ml in each.
2. Weigh the mass of the shells using an electronic balance and ensure that both shells X and Y are 5g each.
3. Put shell X in one beaker and shell Y in another and allow the shells to fully react with the acid which can be seen when shells X and Y stop decreasing in size.
4. When the reaction is completed, remove both shells from their beakers and dry them with a cloth.
5. Measure the new mass of each shell using an electronic balance.
6. Calculate the mass lost for each of the shells by taking the initial mass - new mass.
7. Repeat the experiment several times and collate the results in a table. Then compare which shell type, X or Y, loses more mass.
8. The shell that loses the most mass has the higher percentage of Calcium Carbonate.

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constant variables:
1. Type of acid
2. Volume of acid used
3.Mass of seashell
Changed variables:
1.Seashell

Procedure:
1.Place seashell X in a test tube   beaker/conical flask
2.Add excess HCl into the test tube containing the seashell X
3.Collect the amount of CO2 gas produced from the reaction using the gas syringe method via the downward delivery method
4.Place seashell Y into a test tube
5.Repeat steps 1 to 3 while ensuring that the amount of HCl used is the same amount as the first time round
6. Compare the amount of CO2 gas collected from both the experiments. The experiment that has collected more CO2 gas is the seashell that has a higher percentage of calcium carbonate.

Apparatus to be used:
1.Gas syringe
2.Delivery tube
3.Test tubes

Quantity to be measured:
The amount of CO2 gas collected from the reaction of seashell and HCl acid

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Approach:
1. add excess HCl to both seashells
2. measure mass of residue obtained when effervescence has ceased

Variables:
-changed variables
>type of shell (X, Y)
-constant variables
>volume of HCl acid added to both seashells
>initial mass of seashells
>size/contact surface area of seashells with acid
-measured variables
>mass of residue obtained.

Apparatus needed:
-electronic balance
-measuring cylinder
-3 pieces of filter paper
-filter funnel
-conical flask

Steps:
1.measure mass of seashell X using electronic balance (m1)
2. add 100cm3 of excess HCl acid to seashells. use measuring cylinder to obtain 100cm3 of HCl first.
3. After effervescence has stopped, filter mixture using filter paper and filter funnel to obtain residue.
4. Dab residue dry with 2 pieces of filter paper.
5. measure mass of residue using electronic balance. (m2)
6. repeat steps 1 to 6 using seashell Y
Data Processing:
6. Calculate percentage of CaCO3 in seashell X and Y by taking (m1-m2)/m1 x 100%

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Constant Variables: 1) initial mass of the seashells
2) the volume of acid used in both reactions
3) type of flasks used

Independent variable: the seashell used

Dependent variable: the final mass of the seashell

Steps:

1) Weigh the mass of the two seashells using an electronic balance, and record the masses as M1 and M2

2) Add 100 ml of hydrochloric acid in excess to both seashells in separate conical flasks

3)wait for the reaction to stop which is when there is no more effervescence

4) filter the mixture using a filtration funnel to obtain the residue seashell and dry the residue using filter paper

5) weigh the final mass of the seashells and record it as FM1 and FM2

6) calculate the percentage mass change by subtraction the intial mass from the final mass, divide it by the initial mass and multiply it by 100%, e.g. FM1 - M1 /M1 x 100%

7) compare the percentage change

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Faiz & Ariel
steps:
1. Put 5g of shell X and 5g of shell Y into 2 separate conical flasks.
2. Add an equal amount  VOLUME of excess H2SO4 into both conical flasks.
3. Stopper the reaction and collect  measure the CO2 gas in gas syringe.
4. Record volume of CO2 collected for both reactions.
5. Record in a table
6. Repeat steps 1 to 4 and find the average of both volumes of CO2 collected for each flask.
7. The reaction which produces more CO2 has a higher percentage of CaCO3

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timothy and jiayi

Required apparatus :
2 Beakers
Seashells
Acid
Timer
Electronic balance
Filter funnel, filter paper

Variable to change : Shell used
Variable to keep constant :
Type of beaker
Time of experiment
Type of seashell used
Type of acid
Variable to measure : Initial seashell mass, mass of residue at end of experiment
Data to process : Mass lost by seashell

1. Weigh initial seashell X with an electronic balance and record in table.
2. Add excess hydrochloric acid to a beaker containing the seashell and time for 30 minutes   (cannot assume reaction has ended)
3. After 30 minutes, filter the mixture using filter paper and dry the residue.
4. Weigh residue on electronic balance and record value.
5. Calculate the difference by taking the value of Step 1 and deducting the value from step 4. Record final value.
6. Repeat step 1 to 5 with Seashell Y.

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Renish and Jonavan
Procedures:
1. Measure the mass of seashells in a beaker using the electronic balance. Take 10g of each seashell sample.
2.Add excess HCl into the seashell sample X in the first conical flask and measure the total mass to check how much HCl has been used. Upon adding the excess HCl, cover the mouth of the conical flask with a stopper to prevent CO2 from escaping.
3. Measure the mass of HCl that you are going to use in another beaker and add it into the conical flask containing the sample of seashell Y.
4. Upon
Constant variables:
-Type of acid used
-Mass of acid used
-Mass of seashell sample used
Changed variables:
-Type of seashell (percentage of CaCO3)
Dependent variable:
-Change in mass
Apparatus needed:
-2 Beakers
-Electronic balance