Answer:
1. a)
2. a)
3. b)
4. d)
Explanation:
The disposal method is how we throw away the wastes. In a chemical lab, the correct disposal method guarantees the security of the environment and the humans and animals that may be in contact with the materials.
So:
1. Excess chemical: Because it can be toxic, it may be disposed of in the appropriate waste container, which will depend on the characteristics of the material;
2. Reaction mixture: As the excess chemical, it can be toxic, so it must be disposed of at an appropriate waste container;
3. Used filter paper: Generally, the solids in the filter paper is not toxic, so it can be thrown away in the trash can;
4. Cracked or chipped beaker: Because the beaker is made of glass, it can cut when broken, so it must go to a broken glass box, that will protect the people that will deal with it.
- The chemical symbol of the isotope boron-11 is ¹¹B.
- The atomic mass of the isotope boron-11 is equal to 11.009306.
- The abundance in nature of the isotope boron-11 is equal to 80.1%.
<h3>What is an isotope?</h3>
An isotope can be defined as the atom of a chemical element that has the same number of protons but different number of neutrons. This ultimately implies that, the isotopes of an element have the same atomic number (number of protons) but different atomic mass (number of neutrons).
In Chemistry, there are two main isotopes of boron and these include the following:
Boron-11 is the most stable isotope of boron and it is characterized by the following:
- The chemical symbol of the isotope boron-11 is ¹¹B.
- The atomic mass of the isotope boron-11 is equal to 11.009306.
- The abundance in nature of the isotope boron-11 is equal to 80.1%.
Read more on Boron-11 here: brainly.com/question/6283234
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Answer:
1 M
Explanation:
The molarity of a solution, M, is a measure of the concentration of that solution and it refers to the number of moles of solute (mol) per liter (L) of solution. The molarity (M) can be calculated using the formula:
M = number of moles (n) /volume (V)
In this question, a 500 ml aqueous solution of Na3PO4 was prepared using 82g of the solute.
Molar mass of Na3PO4 = 23(3) + 15 + 16(4)
= 69 + 31 + 64
= 164g/mol
Mole = mass/molar mass
mole = 82/164
mole = 0.5 mol
Volume in Litres (L) = 500 ml ÷ 1000 = 0.500L
Therefore, Molarity (M) = 0.5/0.500
Molarity = 1 M or 1 mol/L
Answer:
Mass = 20 g
Explanation:
Given data:
Number of moles of He = 5 mol
Mass of He = ?
Solution:
Formula:
Number of moles = mass/ molar mass
Molar mass = 4 g/mol
by putting values,
5 mol = Mass / 4 g/mol
Mass = 5 mol × 4 g/mol
Mass = 20 g
Answer:
The answer to your question is given after the questions so I just explain how to get it.
Explanation:
a)
Get the molecular weight of Phosphoric acid
H₃PO₄ = (3 x 1) + (31 x 1) + (16 x 4)
= 3 + 31 + 64
= 98 g
98 g ----------------- 1 mol
0.045 g --------------- x
x = (0.045 x 1) / 98
x = 0.045 / 98
x = 0.00046 moles or 4.6 x 10 ⁻⁴
b)
Molarity = 
Molarity = 
Molarity = 0.0013 or 1.31 x 10⁻³
c)
Formula C₁V₁ = C₂V₂
V₁ = C₂V₂ / C₁
Substitution
V₁ = (0.0013)(1) / 0.01
Simplification and result
V₁ = 0.0013 / 0.1
V₁ = 0.13 l = 130 ml
