A skateboard is pushed up a hill with a 90 N force to the left and experiences a gravitational force of 100 N to the right. (A)
2 answers:
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The empirical formula of the compound : <u><em>RbO₂</em></u>
<h3>Further explanation</h3>Dulong and Petit's rule's rule, which says that the molar heat capacity, Cp, of a solid can be expressed as
Where N is the number of atoms per formula unit and R is the universal gas constant
While the value of R is:
R = 8.3144621 J / K · mol
then:
3R = 24.94 J / K · mol
Heat capactiy per gram of a compound containing rubidium and oxygen is 0.64 J · K⁻¹ · g⁻¹
We try the possible empirical formula from the composition of Rb and O
- Rb₂O
So the number of atoms: 3 (Rb = 2 atoms, O = 1 atom)
Then the value of the Cp:
Molar mass Rb₂O = 2.85.5 + 1.16 = 187 g/mol
Then this empirical formula Rb₂O is not appropriate
- RbO₂
So the number of atoms: 3 (Rb = 1 atom, O = 2 atoms)
Then the value of the Cp:
Molar mass RbO₂ = 1.85.5 + 2.16 = 117.5 g / mol
Then this empirical formula RbO₂ is appropriate
<h3>Learn more </h3>
chemical bond
ionic bonding
electron dots
Keywords: an empirical formula,compound, gas constant, Dulong and Petit's rule,the molar heat capacity
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Answer:
The empirical formula of this substance is:
Explanation:
To find the empirical formula of this substance we need the molecular weight of the elements Carbon, Hydrogen and Oxygen, we can find this information in the periodic table:
- C: 12.01 g/mol
- H: 1.00 g/mol
- O: 15.99 g/mol
With the information in this exercise we can suppose in 100 g of the substance we have:
C: 48.64 g
H: 8.16 g
O: 43.2 g (100 g - 48.64g - 8.16g= 43.2 g)
Now, we need to divide these grams by the molecular weight:
We need to divide these results by the minor result, in this case O=2.70 mol
We need to find integer numbers to find the empirical formula, for this reason we multiply by 2:
This numbers are very close to integer numbers, so we can find the empirical formula as subscripts in the chemical formula:
Mass of lead (II) chromate is 51 g. The molecular formula is and its molar mass is 323.2 g/mol
Number of moles can be calculated using the following formula:
Here, m is mass and M is molar mass.
Putting the values,
Therefore, number of moles of lead (II) chromate will be 0.1578 mol.
Answer:
The freezing point will be
Explanation:
The depression in freezing point is a colligative property.
It is related to molality as:
Where
Kf=
the molality is calculated as:
Depression in freezing point =
The new freezing point =