The correct answer is - A) The major constituents of air are gaseous elements.
With the statement ''the major constituents of air are gaseous elements'' we can easily conclude that the air is a mixture. The reason for that is that we have a plural usage of the word element, elements, which mean that there are multiple elements that make up the air.
The air is indeed predominantly a mixture of gaseous elements. The most abundant gas in the air being the nitrogen with 78.9%, oxygen with 20.95%, argon 0.93%, and carbon dioxide 0.04%, with lesser amounts of other gases also be present in it. The water vapor is also present in the air, though it is variable, being around 1% at sea level, but only 0.4% over the entire atmosphere.
Answer: Option b. 50 neutrons and 38 protons.
Explanation:
Atomic number = proton number = 38
Mass number = proton number + Neutron
Mass number = 88
Proton = 38
Neutron number =?
Neutron number = Mass number — proton number
Neutron number = 88 —38 = 50
Answer:
2.8 x 10²³ molecules H₂O
1.4 x 10²³ molecules O₂
Explanation:
First, you will need the balanced chemical equation for the formation of water:
2H₂ + O₂ -> 2H₂O
This will help in determining the mole ratios between water and oxygen, which we will need later.
Let's first calculate the number of H₂O (water) molecules. This will require stoichiometry. We are also given the mass, so we must convert mass into moles, then moles into molecules. mass -> moles -> molecules
8.5 g H₂O x (1 mol H₂O/18.01528 g H₂O) x (6.02 x 10²³ molecules H₂O/1 mol H₂O) = 2.8404 x 10²³ molecules H₂O
Rounded to 2 significant digits: 2.8 x 10²³ molecules H₂O
Now, to find the molecules of water, we can begin with the same stoichiometric equation, but before we convert to molecules, we will have to convert moles of water to moles of oxygen. This is where we will use the mole ratio of water to oxygen we got from the balanced chemical equation earlier. 2H₂O:1O₂
8.5 g H₂O x (1 mol H₂O/18.01528 g H₂O) x (1 mol O₂/2 mol H₂O) x (6.02 x 10²³ molecules O₂/1 mol O₂) = 1.4202 x 10²³ molecules O₂
Rounded to 2 significant digits: 1.4 x 10²³ molecules O₂
Empirical formula: Li4OH
Answer:
1 mole: 44.771 g
1 gram = 0.022 mole
Explanation:
Element: Li
Percentage by mass: 62.01%
Number of atoms: 4
Mass of atom;: 6.941
Element: O
Percentage by mass: 35.74%
Number of atoms: 1
Mass of atom: 15.9994
Element: H
Percentage by mass: 2.25%
Number of atoms: 1
Mass of atom: 1.00794
