Hydrogen is the limiting reactant because when doing a stoichiometry equation for the reactants, hydrogen will be used completely by having a smaller yield and oxygen will be excess (7 moles to be exact)
Magnesium is in the second group in the periodic table, which means that its outer shell is an s-orbital which contains 2 valence electrons.
Hydrogen also has an s-orbital as an outer shell but it only contains 1 valence electron. The electron dot diagram would look like this:
H· ·Mg· ·H
Each hydrogen shares one electron with magnesium and the magnesium shares one of its electrons with each hydrogen resulting in two covalent bonds.
H:Mg:H and this gives us the compounds MgH₂
When you cook food like eggs, this is a chemical change. Agree.
The runny egg turns into a solid. One type of matter must be changing into another type
When you cook food like potatoes, this is a chemical change. Agree.
Boiling potatoes causes changes in the structure of the starch. Higher heat as in baking, roasting, or frying causes the development of a harder crust on the potato. This suggests that chemical changes have taken place.
When a candle burns, the wick of the candle and wax turn into nothing. Disagree.
The <em>Law of Conservation of Mass</em> says that <em>you can’t turn matter into nothing</em>. What must be happening is that the wick and the wax are changing into other substances that we can’t see, such as colourless gases of carbon dioxide and water vapour.
Answer:
Li₂CO₃ ⇒ Li₂O + CO₂ is a decomposition reaction.
Explanation:
In a decomposition reaction, a single substance decomposes, producing two or more different substances. In other words, in this type of reaction two or more substances are formed from a compound. The atoms that form a compound separate to give the products according to the formula:
AB → A + B
It can occur spontaneously, or be aided by a catalyst, heat, or electrolysis.
In this case:
Li₂CO₃ ⇒ Li₂O + CO₂ It is a type of chemical reaction in which a single compound decomposes into two or more compounds. So it is a decomposition reaction.
Answer:
1) the product may be contaminated by the solvent
2) side reactions may yield unwanted products
3) some reactants may be present in the product if the reaction was incomplete
Explanation:
It is common in chemistry to pass reaction products through purification processes. This is done for a number of reasons.
First of all, some solvents molecules may be attached to the reaction product. These solvent particles must be separated in order to obtain a pure product.
Secondly, some side reactions also yield products that are isolated along with the desired products and these must be separated accordingly.
Finally, some chemical reactions do not go on to completion. This implies that some reactants may still be isolated alongside the product at the end of the reaction.
