Answer:
Find the steps and explanation below.
Explanation:
A. Kids make slime following these basic steps;
1. In a bowl, is 1/4 cup of water is added to 1 oz. of glue. Add coloring if you wish to.
2. 1/4 cup of Borax solution, also known as Sodium Tetraborate is added to the mixture and gradually stirred.
3. The mixture is kneaded with the hands to ensure a smooth consistency.
4. Water remnants are discarded and the slime is stored in a plastic bag and kept in the fridge.
B.
What each ingredient does
Polyvinyl acetate present in the glue acts as a liquid polymer.
Borax binds the liquid polymers together.
Water eases the mixing process
C.
If lesser ingredients are used, the slime will not have its characteristic slimy nature. If excess of the ingredients are used, the slime becomes very sticky.
Silicon is a popular semi-conductor. The process of doping either creates an excess or lack of electrons. In the case of silicon, the dopant is arsenic which has greater valence electron than silicon. Arsenic then donates an electron resulting to an excess of electrons. A new type or better type of semi-conductor is created. Silicon conduct greater electricity.
The best answer is the last option.
Answer:
Na₂CO₃.2H₂O
Explanation:
For the hydrated compound, let us denote is by Na₂CO₃.xH₂O
The unknown is the value of x which is the amount of water of crystallisation.
Given values:
Starting mass of hydrate i.e Na₂CO₃.xH₂O = 4.31g
Mass after heating (Na₂CO₃) = 3.22g
Mass of the water of crystallisation = (4.31-3.22)g = 1.09g
To determine the integer x, we find the number of moles of the anhydrous Na₂CO₃ and that of the water of crystallisation:
Number of moles = 
Molar mass of Na₂CO₃ =[(23x2) + 12 + (16x3)] = 106gmol⁻¹
Molar mass of H₂O = [(1x2) + (16)] = 18gmol⁻¹
Number of moles of Na₂CO₃ = 
= 0.03mole
Number of moles of H₂O = 
= 0.06mole
From the obtained number of moles:
Na₂CO₃ H₂O
0.03 0.06
Simplest
Ratio 0.03/0.03 0.03/0.06
1 2
Therefore, x = 2
Answer:
Magnesium oxide is a binary compound of magnesium and oxygen while magnesium ribbon consists only of magnesium atoms.
Explanation:
The burning of magnesium in oxygen is a chemical change. It produces magnesium oxide having greater mass than magnesium ribbon. The greater mass results from the fact that the chemical reaction has added another element to the sample- oxygen. The mass of magnesium ribbon is the mass of magnesium atoms alone but in magnesium oxide, we consider the masses of magnesium and oxygen atoms making magnesium oxide heavier than magnesium ribbon.
