On the periodic table, the elements colored yellow, which generally border the stair -step line , are considered to be metalloids
Answer:
a. Amadeo Avogadro (1776-1856) was the author of Avogadro's Hypothesis in 1811, which, together with Gay-Lussac's Law of Combining Volumes, was used by Stanislao Cannizzaro to elegantly remove all doubt about the establishment of the atomic weight scale at the Karlsruhe Conference of 1860. The name "Avogadro's Number" is just an honorary name attached to the calculated value of the number of atoms, molecules, etc. in a gram mole of any chemical substance. Of course if we used some other mass unit for the mole such as "pound mole", the "number" would be different than 6.022 x 1023.
b. The first person to have calculated the number of molecules in any mass of substance was Josef Loschmidt, (1821-1895), an Austrian high school teacher, who in 1865, using the new Kinetic Molecular Theory (KMT) calculated the number of molecules in one cubic centimeter of gaseous substance under ordinary conditions of temperature of pressure, to be somewhere around 2.6 x 1019 molecules. This is usually known as "Loschmidt's Constant.
Task 2
a.
Percent composition is the percent by mass of each element present in a compound. Water, H2O, is the first example. One mole of water is 18.0152 grams. In that compound, there are two moles of H atoms and 2 x 1.008 = 2.016 grams. That's how many grams of hydrogen are present in one mole of water. this is an example. i don't know what you are describing though. i need more info for this question
b. 6.022 to 6.023 x 10^23
c. i don't know what this one is since there is nothing to describe the unknown liquid.
d. Yes a killer, but not a specific person
Explanation:
Answer:
Explanation:
<u>1. Convert Grams to Moles</u>
Use the molar mass (found on the Periodic Table) to convert from grams to moles.
Use this value as a ratio.
Multiply by the given number of grams.
Flip the ratio so the grams of boron cancel out.
<u>2. Convert Moles to Atoms</u>
We use Avogadro's Number, 6.02*10²³: the number of particles (atoms, molecules, etc.) in 1 mole of a substance. In this case, the particles are atoms of boron.
Multiply by the number of moles we calculated.
The moles of boron cancel.
The original value of grams has 4 significant figures, so our answer should have the same. For the number we calculated, that is the thousandth place.
The 6 tells us to round the 2 to a 3.
25.00 grams of boron is equal to 1.393*10²⁴ atoms.
On a molecular level there is a lot of movement which in turn is the reason why heat is generated.
