As a result of high winds and water from a storm surge, homes, businesses, and crops may be destroyed or damaged, public infrastructure may also be compromised, and people may suffer injuries or loss of life.
3, 1, 5, 4, 3, spontaneous
The correct number of protons 20. If it is calcium, it has to be 20 protons. 27 is the number of neutrons.
Answer:
Avogadro’s Number
Avogadro’s NumberIt certainly is easy to count bananas or to count elephants (as long as you stay out of their way). However, you would be counting grains of sugar from your sugar canister for a long, long time. Atoms and molecules are extremely small – far, far smaller than grains of sugar. Counting atoms or molecules is not only unwise, it is absolutely impossible. One drop of water contains about 10 22 molecules of water. If you counted 10 molecules every second for 50 years without stopping you would have counted only 1.6 × 10 10 molecules. Put another way, at that counting rate, it would take you over 30 trillion years to count the water molecules in one tiny drop.
Avogadro’s NumberIt certainly is easy to count bananas or to count elephants (as long as you stay out of their way). However, you would be counting grains of sugar from your sugar canister for a long, long time. Atoms and molecules are extremely small – far, far smaller than grains of sugar. Counting atoms or molecules is not only unwise, it is absolutely impossible. One drop of water contains about 10 22 molecules of water. If you counted 10 molecules every second for 50 years without stopping you would have counted only 1.6 × 10 10 molecules. Put another way, at that counting rate, it would take you over 30 trillion years to count the water molecules in one tiny drop.Chemists needed a name that can stand for a very large number of items. Amedeo Avogadro (1776 – 1856), an Italian scientist, provided just such a number. He is responsible for the counting unit of measure called the mole. A mole (mol) is the amount of a substance that contains 6.02 × 10 23 representative particles of that substance. The mole is the SI unit for amount of a substance. Just like the dozen and the gross, it is a name that stands for a number. There are therefore 6.02 × 10 23 water molecules in a mole of water molecules. There also would be 6.02 × 10 23 bananas in a mole of bananas, if such a huge number of bananas ever existed
The mass of ore required is
21 700 t.
r = 750 cm
V =
=
= 1.767 × 10⁹ cm³
The density of lead is 11.34 g/cm³.
So mass of lead sphere = 1.767 × 10⁹ cm³ ×
= 2.004 ×10¹⁰ g
2.004 ×10¹⁰ g ×
= 2.004 × 10⁷ kg
2.004 × 10⁷ kg ×
= 2.004 × 10⁴ t
92.5% efficiency means 92.5 t Pb per 100 t of ore.
Mass of ore = 2.004 × 10⁴ t Pb ×
= 2.17 × 10⁴ t ore = 21 700 t ore
