Q&A Why

Why the total mass of the products would be less than the total weight of the reactants after a chemical reaction?

Although mass can be rearranged or change in form, it cannot be created or destroyed during a chemical reaction. In short, the total mass of the starting materials (reactants) will equal the mass of the product. This statement summarises the Law of Conservation of Mass.

When, during an experiment, you find there is less mass in your test beaker, the nuance to understand is that not all formed products stay in the test measurement vessel. Often during a reaction, we will see losses in mass in the form of gaseous elements. Unless you cap your test vessel tightly, a change in mass may occur.

This experiment is an easy way to test the mass conservation principle's efficacy using an effervescent tablet. An effervescent tablet comprises granulated ingredients packed into a dense form, designed to dissolve in contact with water. Effervescence is the escape of gas from an aqueous solution resulting in fizzing or foaming. The tablet will breakdown in water; for many types of effervescent tablets, the element most often released is carbon dioxide.

The Design of the Experiment

At the beginning of the experiment, we will weigh the water and effervescent tablet. Then every 30 seconds as the tablet dissolves, we will take additional measurements until the tablet completely dissolves and determine any mass loss. We will then repeat the same procedure, but this time with an identical tablet and capped bottle.

Materials Used

Room temperature water
Glass Beaker
A glass beaker with a bung (or a container tightly capped to create a closed system)
Navigator Multi-purpose Balance
Effervescent tablet; and
Stopwatch.

Method

On the Navigator Multi-purpose Balance, place the empty beaker and tare it.
Pour 200mL of water into the beaker.
Place the effervescent tablet onto the scale next to the beaker and record the total weight.
Add the effervescent tablet to the beaker and start the stopwatch. Record the mass every 30-seconds until seven minutes have elapsed.
Remove the beaker from the scale.
Pour 200mL of water into the second beaker.
Place the effervescent tablet onto the scale next to the beaker and record the total weight.
Add the effervescent tablet to the beaker, cap the top of the container, and start the stopwatch. Record the mass every 30-seconds until five minutes have elapsed.
After five minutes have elapsed, open the container, record the weight for a further two minutes.

Results

Time	Open Beaker	Capped Container (Closed System)
0:00	1	2
0:30	1	2
1:00	1	2
1:30	1	2
2:00	1	2
2:30	1	2
3:00	1	2
3:30	1	2
4:00	1	2
4:30	1	2
5:00	1	2
5:30	1	2
6:00	1	2
6:30	1	2
7:00	1	2

For the open beaker, the combined mass of water and effervescent tablet started as XX. When wholly dissolved, the final mass of the remaining product was XX – i.e., a reduction of XX.

The capped beaker held a steady mass for the first five minutes of the experiment. With the release of formed gases, we observed a total mass reduction of XX.

Conclusion

After the final step of our experiment, we observed that the mass of both the open beaker and the closed container had reduced. With our open sample, we recorded a steady reduction in weight as time elapsed. In the 'closed system,' i.e., our capped sample, the trapped gas and liquid's combined mass remained unchanged, but the mass suddenly decreased when gas was allowed to escape.

Don't fret - No mass was harmed (or created) in the making of this experiment. We concluded that; the Conservation of Mass principle holds and that the effervescent reaction merely resulted in a release of gas into the surrounding air.

Should you have any experiments you would like our team of scientists to undertake and share with Instrument Choice customers, feel free to contact us! Call 1300 737 871 or email [email protected].

the balanced equation.
the mass of the limiting reactant and.
the A r (relative atomic mass ) or M r (relative formula mass ) values of the limiting reactant and the product.

If you start with 10 g of reactant you must end up with 10 g of product. 5.6 g of the product is calcium oxide so 10 – 5.6 = 4.4 g of carbon dioxide.

How does the total mass of the products of a chemical reaction compare with the total mass of the reactants?

The law of conservation of mass states that in a chemical reaction the total mass of reactants is equal to the total mass of products. … Because atoms are rearranged in a chemical reaction there must be the same number of sodium atoms and chlorine atoms in both the reactants and products.

What is the mass of products in a chemical reaction?

The mass of the products is the same as the mass of the reactants in any chemical reaction.

When 4g of zinc react with 1 g of oxygen What mass of zinc oxide is produced?

5g ( 4+1 ) of zinc oxide. According to law of conservation of mass mass can neither be created nor be destroyed in a chemical reaction.

What is produced during the replacement reaction of Cu NO3 2 and Zn?

Explanation: When you add a strip of zinc metal to a solution of copper(II) nitrate a single replacement reaction takes place. Zinc will displace copper from the solution. This will result in the formation of aqueous zinc nitrate Zn(NO3)2 and copper metal Cu .

What is the molar mass of HCl?

36.458 g/mol

What is the total mass before a reaction?

The total mass before a chemical reaction………… is EQUAL to the total mass after a chemical reaction. Mass is conserved in EVERY chemical reaction. This is why educators place such emphasis on stoichiometry which requires that mass and atoms and molecules are balanced.

Can the mass of a product or products be greater than the total mass of reactant or reactants )?

Re: Mass of Reactant/Product

This is how you are easily able to determine how much of a product was made as a result of a limiting reactant.

What is the total mass before a chemical reaction equals?

Law of Conservation of Mass
The Law of Conservation of Mass dates from Antoine Lavoisier’s 1789 discovery that mass is neither created nor destroyed in chemical reactions. In other words the mass of any one element at the beginning of a reaction will equal the mass of that element at the end of the reaction.

What is a total mass?

The total mass of the compound is the sum of the mass of the two hydrogen atoms and one oxygen atom. mass percent = (mass of element in 1 mole of compound / mass of 1 mole of compound) x 100.

What is the total mass of compound?

The molecular mass or molecular weight is the total mass of a compound. It is equal to the sum of the individual atomic masses of each atom in the molecule.

How do you find the total mass of a compound?

The molar mass is the mass of a given chemical element or chemical compound (g) divided by the amount of substance (mol). The molar mass of a compound can be calculated by adding the standard atomic masses (in g/mol) of the constituent atoms.

How do you find the maximum mass produced in a reaction?

What is the maximum mass that can be produced?

A theoretical yield is the maximum possible mass of a product that can be made in a chemical reaction. It can be calculated using: the balanced equation. the mass and relative formula mass of the limiting reactant.

How do you find the mass of a product given the mass of the reactants?

What happens to the total mass in a chemical reaction?

In a chemical reaction the total mass of all the substances taking part in the reaction remains the same. Also the number of atoms in a reaction remains the same. Mass cannot be created or destroyed in a chemical reaction.

How does the mass of the products in a chemical reaction compare to?

In a chemical reaction how does the mass of the reactants compare with the mass of the products? During a chemical reaction the mass of the products is always equal to the mass of the reactants.

Why does mass increase in a chemical reaction?

Mass is never lost or gained in chemical reactions. We say that mass is always conserved. In other words the total mass of products at the end of the reaction is equal to the total mass of the reactants at the beginning. This is because no atoms are created or destroyed during chemical reactions.