LET’S START WITH COPPER

CHEMISTRY REPORT

2012

INTRODUCTION:

The law of conservation of mass means that the atoms of an object cannot be created or destroyed, but can be moved around and be changed into different particles. This law says that when a chemical reaction makes two different atoms into a new product, the mass will be the same. Knowing this the mass of the copper should be the same at the beginning and at the end of the experiment.

In this investigation we will see some chemical changes such as formation of gas, temperature changes, solid formed, color change occurs or a new odor produced and physical changes such as freezing, melting, dissolving evaporating.

Copper is a widely used metal, it is use in …show more content…

Pour as much of the solid you can into this dish, place the dish over a steam bath to get rid of the extra liquid. By the end only a brown solid remain, it’s mass is 1,6g. No chemical reaction occurred in stage 6. The mass of the solid found is the same than the mass of the copper at the start of the experiment; my hypothesis is that the solid found is copper.

DISCUSSION:

-In stage 1 the copper dissolved completely and the solution went blue, a toxic gas was also formed.

Cu(s) + 4HNO3(aq) ( Cu(NO3)2(aq) + 2NO2(g) + 2H2O(l)

-In stage 2 the blue colour turned lighter and the solution heated up.

Cu(NO3)2(aq) + 2NaOH(aq) ( Cu(OH)2(s) + 2NaNO3(aq)

- In stage 3 the colour of the solution changed once again, it went from light blue to dark blue, a solid was formed.

Cu(OH)2(s) J( CuO(s) + H2O(g)

-In stage 4 a substance disappeared and the solution turned into a teal colour.

CuO(s) + H2SO4(aq) ( CuSO4(aq) + H2O(l)

-In stage 5 the liquid went clear, a new solid formed and a chlorine gas formed.

Cu+2(aq) + Zn(s) ( Cu(s) + Zn+2(aq)

After going through that many chemical changes the copper remains the same. The copper found in stage 6 is small, shiny, it has a brown-orange colour, it’s mass is 1.6g. It looks and weights exactly like the copper at the beginning of the experiment. It proves that the law of conservation of matter is