What happens when a piece of Mg ribbon is burnt? Name the new substance formed. Write a balanced chemical equation.

When a Magnesium Ribbon is burnt, a powdery substance called magnesium oxide is formed.

Explanation:

There has obviously been a chemical change because several chemical properties of the magnesium have been modified:  the color, the texture and the mass.

The increase in mass is due to the fact that oxygen from the air has combined with the magnesium to make magnesium oxide, MgO.

The chemical equation, Mg + O2  MgO shows this reaction but it needs to be balanced to make 2Mg + O2  2MgO.  

Using stoichiometry, we can convert this eqation into an equation with moles:  

2 mol Mg + 1 mol O2  2 mol MgO.  

Next, we convert to grams using atomic masses obtained from the periodic table:

48g Mg + 32g O2  80g MgO

Lastly, we determine the same thing in the proportions we used.  In other words, we used only 0.15g of Mg (not 48g) so everything needs to be divided by 320.  So 80 / 320 = 0.25 g.  If we burn 0.15 g of Mg, we obtain 0.25 g of MgO.

Hope this helps!!!

This is my first answer.

atomic mass = 39

number of neutrons = 20

number of protons= 19

electronic configuration = 1s2 2s2 2p6 3s2 3p6 4s1

the number of electron in first shell = 2

number of electrons in n=3 shell = 8

substituting a hydrogen atom with a halogen in a hydrocarbon:

- the single bond remains single. a is wrong.

- the bond with hydrogen is as strong as with a halogen. c is wrong

- a hydrocarbon is saturated if there is no double bond. we do not know that so d is wrong.

- carbon will always have four valence electrons. e is wrong.

by elimination, the correct answer is b. the boiling point of the new compound increases.