Chemistry investigation

Law of Conservation

• The Law of Conservation of Mass states that mass is conserved in a closed system during a chemical reaction

• Means that Mass cannot be created nor destroyed only rearranged or transformed

• Total mass of reactants = total mass of products

Reactants

Substance present at the start of the reaction (left)

Products

The new substance formed

Elements

Pure substances formed with one kind of atom H₂, Ca

Molecules

Substance where two or more different or same atoms are bonded together CO₂ H₂

Compound

Substance formed when different elements bond at a fixed ratio

Hydrogen pop test equations

HCl+Mg→MgCl₂+H₂ 2HCl+Mg→MgCl₂+H₂

Hydrogen pop test indication

Hydrogen gas- Highly flammable hydrogen gas rapidly combusts with atmospheric gas creating a pop sound

Limewater test equations

CaCO₃+HCl→CO₂+CaCl₂+H₂O

CaCO₃+2HCl→CO₂+CaCl₂+H₂O

Limewater test indication

Carbon dioxide- CO₂ Reacts with limewater and turns into insoluable precipitate of calcium carbonate causing the clear limewater to turn white or snowy

Oxygen tetst equation

H₂O₂→H₂O+O₂

2H₂O₂→2H₂O+O₂

oxygen test indication

Oxygen gas- Since oxygen is required for combustion, the concentrated gas causes the glowing splint to reignite

Independent variable

The variable that you change

Dependent variable

the variable that you measure

controlled variable

the variable that you keep the same

General carbonate formula

Metal Carbonate + acid →Carbon dioxide + Water +metal salt

BUT IF ACID IS HCl, it becomes metal chloride

Risks and how to reduce them

Risks	How to reduce them
HCl is a corrosive acid that irritates skin if in direct contact	Wear gloves, goggles, lab coat
A match is an open flame that can burn your skin if in direct contact (also leads to fires	Keep an eye on the flame and use heat-proof mats
Glass can be broken, which can pierce skin if left unattended	Carry equipments with two hands and carefully

Signs of chemical indication

• Colour change

• Precipitate formation (solid divides from liquid)

• Gas formation (bubbles, fizzing)

• Temperature changes

• Light or smell

reason why law of conservation is important in balancing chemical equations

Chemical equations must be balanced so that there is the same number and type of atoms on both the reactant side and the product side of equations, as atoms cannot be created or destroyed.