Answer:
What Structures??
Explanation:
Can you please explain the question more
It is false, the atomic number is the number of protons and/or electrons in an atom on an element.
Answer:
- <em>The average mass of calcium in each sample is: </em><u>0.978 g</u>
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- <em>The absolute uncertainty is: </em><u>0.008 g</u>
Explanation:
The <em>absolute uncertainty </em>of the total samples indicated in the statement is ± 0.1 g.
When you multiply or divide quantities with uncertainties, you calculate the final uncertanty by adding the <em>relative uncertainties</em> together.
The relative uncertainty is the absolute uncertainty divided by the quantity:
- Relative uncertainty = 0.1g / 12.2 g = 0.008
The average mass of calcium is calculated using proportions, along with the molar masses:
- Molar mass of calcium: 40.078 g/ mol (from a periodic table)
- Molar mass of calcite: 100.085 g/mol (given)
Proportion:
- 40.078 g of calcium / 100.085 g of calcite = x / 12.2 g of calcite
- x = 12.2 × 40.078 / 100.085 g = 4.89 g calcium
So the total mass of calcium in the five samples is 4.89 g, and the average mass in each sample is:
- Average mass = total mass of five samples / number of samples
- Average mass = 4.89 g / 5 = <u>0.978 g of calcium</u>
So, the first answer is that the average mass of calcium in each sample is 0.978 g ( keep 3 signficant figures, such as the quntitiy 12.2 shows, as you have only used multiplication and division).
The absolute uncertainty of each sample is the relative uncertainty multiplied by the average mass of calcium of the five samples, rounded to one decimal:
- Absolute uncertainty = 0.978 g × 0.008 ≈ 0.008 g
The answer to the secon question is that the absolute uncertaingy of calcium in each sample is 0.008 g.
Answer : The correct answer is option 2 : 0.10 M NaCl and 0.10 M NaClO₄
Explanation :
Solutions are classified into 3 categories.
1) Strong electrolytes : These are the solutions that dissociate completely forming ions . They are good conductors of electricity.
Example : All strong acids, bases and the salts made by strong acid/base are strong electrolytes .
2) Weak electrolytes : These substances do not dissociate completely thereby forming fewer ions. They are weak conductors of electricity.
3) Non electrolytes : These are the substances that do not dissociate at all. They do not form ions in aqueous medium. They are bad conductors of electricity.
Let us take a look at the given options and find out what type of solution do we have .
Option 1 : NH₃ is a weak electrolyte whereas NH₄Cl is a strong electrolyte bcause NH₄Cl is made by combination of NH₃ and HCl ( HCl is a strong acid)
Therefore NH₃ would carry electricity less efficiently than NH₄Cl.
Option 2 : Both NaCl and NaClO₄ are strong electrolytes. Therefore they will conduct electrical current equally well
Option 3 : NaNO₃ is a strong electrolyte but HNO₂ is a weak electrolyte. Therefore they will not carry the current equally
Therefore the correct option is option 2
