Answer:
<h2>HERE'S YOUR ANSWER </h2>
We are given that the ring is made up of 20 carrat gold. 20 carrat gold means 20 parts of gold and 4 parts of other metal (usually copper or silver). Thus, the percentage of gold in 20 carrat gold will be
= (20 / 24) X 100
= 83.333 %
We can now calculate the mass of gold in the ring. We are given that the ring weighs 300 mg. So, the mass of gold in ring will be
= (83.333 / 100) X 300
= 250 mg
Thus, the mass of gold in 300 mg of the ring is 250 mg.
Now the molar mass of gold is 197 g. This means that there are 6.023 X 1023 atoms of gold in 197g of gold. Thus
197g of gold = 6.023 X 1023 atoms of gold
1g of gold = (6.023 X 1023 ) / 197 atoms of gold
250 mg or 0.25g of gold = (6.023 X 1023 X 0.25) / 197 atoms of gold
= 7.643 X 1020 atoms of gold
<h2>HOPE IT HELPS MAN ☺️</h2>
Answer:
a) 1.6
f)7.51
b)3.9
g)9.2
c)3.1
h)41.9
d)1.959
i)0.29
e)5.2
j)1.112
Explanation:
When you are multiplying or dividing the numbers you take the least amount of significant figures and that's how many significant figures your answer will be. Instead of being a super long answer. Hope this helps. Also, sorry it took me a hot minute :)
Answer: (3) decomposition and melting
Explanation: Chemical change is one in which chemical composition of substance changes.
Physical change is one in which chemical composition of substance do not change.
Freezing is a process in which a liquid changes into solid phase when allowed to cool. Thus it is a physical change.
Melting : It is process in which a solid changes into liquid phase by providing heat. Thus it is a physical change.
Vaporization : It is process in which liquid changes into gaseous phase by providing heat. Thus it is a physical change.
Decomposition is a chemical reaction in which one substance decomposes to form two or more than two products. Thus the chemical composition change, and hence is a chemical change.
Combustion is a reaction in which a substance combines with oxygen gas to produce carbon dioxide, water and a lot of heat. Thus the chemical composition change, and hence is a chemical change.
The word for horizontal rows of the periodic table is a period
