An element is a pure substance made up of only one kind of atom. An element is composed of atoms in which it is composed of neutrons and protons. The nucleus is surrounded by electrons. The answer to this problem is A. element
Answer:
4.3 moles of Fe2O3
Explanation:
The calculations are shown in the picture.
Answer:
A solution of acetic acid that is 60.0% HC₂H₃O₂ (by mass) indicates that it contains 60.0 g of acetic acid and 100.0 g of water.
Explanation:
A percentage is a way of expressing an amount as a fraction of 100. The mass percentage corresponds to physical units of the solutions and they allow to establish more precisely the concentration of the solutions and express them in terms of percentages.
Mass percentage indicates the amount in grams of solute per 100 grams of solution.
So a solution of acetic acid that is 60.0% HC₂H₃O₂ (by mass) indicates that it contains 60.0 g of acetic acid and 100.0 g of water.
<u><em>Answer:</em></u>
- A pure substance that contains more than one atom is called a compound.
<u><em>Explanation:</em></u>
- Compounds are formed by combination of atoms by a fixed ratio. They have their own characteristic features.
- Pure substances are further broken down into elements and compounds. A compound can be destroyed by chemical means. It might be broken down into simpler compounds, into its elements or a combination of the two.
<u><em>Example </em></u>
- H2SO4 which is formed by combination of three different atoms like H, S and O.
Answer:
156 g
Explanation:
Let's consider the following reaction.
2 NaN₃(s) → 2 Na(s) + 3 N₂
(g)
We can find the moles of N₂ using the ideal gas equation.
P × V = n × R × T
1.50 atm × 60.0 L = n × (0.08206 atm.L/mol.K) × 305 K
n = 3.60 mol
The molar ratio of N₂ to NaN₃ is 3:2. The moles of NaN₃ are:
3.60 mol N₂ × (2 mol NaN₃ / 3 mol N₂) = 2.40 mol NaN₃
The molar mass of NaN₃ is 65.01 g/mol. The mass of NaN₃ is:
2.40 mol × 65.01 g/mol = 156 g
