Answer:
The percentage (by mass) of KBr in the original mixture was 33.1%.
Explanation:
The mixture of KCl and KBr has a mass of 3.595g, thus the sum of the moles of KCl (<em>x</em>) multiplied by it molar mass (74.5g/mol) and the moles of KBr (<em>y</em>) multiplied by it molar mass (119g/mol) is the total mass of the mixture:
Also, after the conversion of KBr into KCl, the total mass of 3.129 g is only from KCl moles, hence
But the 0.042 moles came from the originals KCl and KBr moles, thus
Now it is possible to propose a system of equations:
Solving the system of equations,
0.010 moles of KBr multiplied it molar mass is
Therefore, the percentage (by mass) of KBr in the original mixture was:
%
It means the relationship between two systems connected only by a diathermic wall.
Barometer, it is used to measure air pressure
Answer:
Al2(SO4)3
Explanation:
Looking at this carefully, we will discover that Al2(SO4)3 is composed of Al^3+ and SO4^2-.
The aluminum and sulphate ions are ionically bonded. However, the oxygen and sulphur in the sulphate ion are covalently bonded.
Hence, Al2(SO4)3 contains both ionic and covalent bond.
Answer:
Melamine is used for making tableware,cooking utensils, plates, plastic products etc.
Explanation:
Melamine is used to manufacture many products. How? Well melamine-formaldehyde resin, as it's full name, forms molecular structures that are molded, with heat, to take the shape of the items such as tableware.
After this chemical reaction takes place, the "left over" remains as plastic.
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And so, it is used in products such as cooking utensils, plates, plastic products etc.
