Answer:
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Answer:
a. When one substance transfers electrons to another.
Explanation:
The redox reaction occurs when one substance oxides and other reduces. To oxide, the compound must lose electrons, and to reduce, it must gain electrons. So, when it's observed that electrons are being transferred, we can tell that a redox reaction is happening.
The oxygen is a good oxidation agent and intends to reduce, but the combustion reaction, for example, involves oxygen and it's not a redox reaction. The reaction between a metal and a nonmetal not necessarily will be a redox reaction.
Answer: There are atoms of hydrogen are present in 40g of urea, .
Explanation:
Given: Mass of urea = 40 g
Number of moles is the mass of substance divided by its molar mass.
First, moles of urea (molar mass = 60 g/mol) are calculated as follows.
According to the mole concept, 1 mole of every substance contains atoms.
So, the number of atoms present in 0.67 moles are as follows.
In a molecule of urea there are 4 hydrogen atoms. Hence, number of hydrogen atoms present in 40 g of urea is as follows.
Thus, we can conclude that there are atoms of hydrogen are present in 40g of urea, .