Answer: -
2.5 moles of calcium atoms are in 2.5 moles of calcium carbonate CaCO₃
Explanation: -
In order to solve such types of problems, the first step would be to write the chemical formula of the compound.
The chemical formula of calcium carbonate = CaCO₃
The chemical symbol of Calcium is Ca.
From the formula of calcium carbonate we can see that
1 mole of CaCO₃ has 1 mole of Ca
2.5 mole of CaCO₃ has 
= 2.5 mol of Ca.
∴2.5 moles of calcium atoms are in 2.5 moles of calcium carbonate CaCO₃
The volume of 15.7 M H2SO4 is required to prepare 12.0 L of 0.156 M sulfuric acid is 0.12 L
<h3>Data obtained from the question</h3>
From the question given above, the following data were obtained:
- Molarity of stock solution (M₁) = 15.7 M
- Volume of diluted solution (V₂) = 12 L
- Molarity of diluted solution (M₂) = 0.156 M
- Volume of stock solution needed (V₁) = ?
<h3>How to determine the volume of the stock solution needed</h3>
The volume of the stock solution needed can be obtained by using the dilution formula as shown below:
M₁V₁ = M₂V₂
15.7 × V₁ = 0.156 × 12
15.7 × V₁ = 1.872
Divide both side by 15.7
V₁ = 1.872 / 15.7
V₁ = 0.12 L
Thus, the volume of the stock solution needed to prepare the solution is 0.12 L
Learn more about dilution:
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Answer:
A. Second
Explanation:
The S.I unit of time is in Seconds.
The S. I unit is known as the metric system is the most commonly used system of reporting scientific measurements in the world today. Other units are the imperial units.
It is the international system of unit used in almost all countries. The seven basic SI units are:
Quantities Units
- Length meters(m)
- Time seconds(s)
- Amount of substance moles(mol)
- Mass kilograms(kg)
- Luminous intensity candela(cd)
- Temperature kelvin(K)
- Electric current ampere(A)
The SI unit of time which measures the duration of an activity or event is therefore given as seconds(s)
Answer:
Mixture
Explanation:
When a prospector scoops up part of the stream bed, the pan contains stream sediments.
An example of an element is C) silver
