(2) They differ in their properties, only.
(3) They differ in their molecular structure and properties.
(4) They do not differ in their molecular structure or properties.
Answer: Option (3) is the correct answer.
Explanation:
When an element exists in two or more different physical forms then they are known as allotropes.
For example, diamond and graphite are both allotropes of carbon.
In graphite, carbon atoms are joined together in sheets of six sided lattice. Whereas in diamond, carbon atoms are joined together in four cornered lattice.
Therefore, as these allotropes are made up of same element so they have similar chemical properties but different physical properties like melting point, boiling point etc.
Also, both of them have different molecular structure.
Thus, we can conclude that the statement the differ in their molecular structure and properties correctly describes diamond and graphite.
b) 22.7
c) 55.6
d) 31.8
e) 45.5
The amount of oxygen needed to oxidize 12.5g of propane is 45.5g.
Stoichiometry is the calculation of the quantitative relationships between the amounts of reactants and products in chemical reactions.
The balanced chemical equation for the combustion of propane is:
C3H8 + 5O2 → 3CO2 + 4H2O
To calculate the amount of oxygen needed to react with 12.5g of propane, we need to use stoichiometry and the molar mass of propane. The molar mass of propane is 44.1 g/mol.
First, we need to convert the mass of propane to moles:
12.5 g C3H8 × (1 mol C3H8 / 44.1 g C3H8) = 0.283 mol C3H8
According to the balanced equation, 5 moles of oxygen are required to react with 1 mole of propane. So, we can calculate the amount of oxygen needed as follows:
0.283 mol C3H8 × (5 mol O2 / 1 mol C3H8) = 1.415 mol O2
Finally, we can convert the moles of oxygen to grams using the molar mass of oxygen, which is 32.0 g/mol:
1.415 mol O2 × 32.0 g O2/mol = 45.1 g O2
Therefore, the answer is e) 45.5 g of oxygen is needed to oxidize 12.5g of propane (C3H8).
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(2) second electron shell
(3) third electron shell
(4) fourth electron shell
According to the electronic configuration, a calcium atom in the ground state electrons which possess least amount of energy are located in first shell.
Electronic configuration is defined as the distribution of electrons which are present in an atom or molecule in atomic or molecular orbitals.It describes how each electron moves independently in an orbital.
Knowledge of electronic configuration is necessary for understanding the structure of periodic table.It helps in understanding the chemical properties of elements.
Elements undergo chemical reactions in order to achieve stability. Main group elements obey the octet rule in their electronic configuration while the transition elements follow the 18 electron rule. Noble elementshave valence shell complete in ground state and hence are said to be stable.
According to the electronic configuration,as the number of shells increases their energy also increases .Hence, electrons in first shell have least energy.
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Answer:
1
Explanation:
first electron shell.
First electron shell possesses the least amount of energy at the core.
Hope this helps.
Answer: The number of atoms in given amount of oxygen gas is
Explanation:
According to the mole concept:
1 mole of a substance contains number of atoms.
We are given:
Moles of oxygen gas = 1 mole
So, the number of atoms that will be present in 1 mole of oxygen gas will be number of atoms.
Hence, the number of atoms in given amount of oxygen gas is