Answer:
0.17 moles
Explanation:
In the elements of the periodic table, the atomic mass = molar mass. <u>Ex:</u> Atomic mass of Carbon is 12.01 amu which means molar mass of Carbon is also 12.01g/mol.
In order to find the # of moles in a 12 g sample of NiC-12, we will need to multiply the number of each atom by its molar mass and then add the masses of both Nickel and C-12 found in the periodic table:
- Molar Mass of Ni (Nickel): 58.69 g/mol
- Molar Mass of C (Carbon): 12.01 g/mol
Since there's just one atom of both Carbon and Nickel, we just add up the masses to find the molar mass of the whole compound of NiC-12.
- 58.69 g/mol of Nickel + 12.01 g/mol of Carbon = 70.7 g/mol of NiC-12
There's 12g of NiC-12, which is less than the molar mass of NiC-12, so the number of moles should be less than 1. In order to find the # of moles in NiC-12, we need to do some dimensional analysis:
- 12g NiC-12 (1 mol of NiC-12/70.7g NiC-12) = 0.17 mol of NiC-12
- The grams cancel, leaving us with moles of NiC-12, so the answer is 0.17 moles of NiC-12 in a 12 g sample.
<em>P.S. C-12 or C12 just means that the Carbon atom has an atomic mass of 12amu and a molar mass of 12g/mol, or just regular carbon.</em>
Answer: only Br2.
Justification.
In a chemical reaction the element that gains electrons experiments a reduction in its oxidation state, that is why it is said that it is reduced.
So, to know what element is being reduced you need to calculate the oxidation states of the elements involved.
Here I indicate the oxidation states of each element if the reaction putting them inside parenthesis:
Reactants side Products side
K (0) K (1+)
Br (0) Br(1-)
So, K lost one electron, increasing its oxidation statefrom 0 to 1+, meaning that it is being oxidized.
And, each atom of Br gained one electron, reducing its oxidation state from 0 to 1-, meaning it is being reduced.
Therefore, the answer is that Br2 is the substance being reduced.
Answer:
The correct answer is option c. transfer of electrons from Mg to O.
Explanation:
Hello!
Let's solve this!
When Magnesium (Mg) reacts with oxygen (O), magnesium oxide is formed.
This reaction is spontaneous and occurs with oxidation number +2 of magnesium and oxidation number -2 of oxygen. It is an ionic union, so magnesium transfers its electrons to oxygen.
We conclude that the correct answer is option c. transfer of electrons from Mg to O.
Answer:
its atomic number
Explanation:
the mass number/atomic mass is how many protons and neutrons are combined in an element. But, the atomic number is just protons.
Explanation:
The given data is as follows.
T = 
= (11 + 273) K = 284 K, V = 45.0 L
m = 35 g
As molar mass of chlorine pentafluoride is 130.445 g/mol. Hence, number of moles of chlorine pentafluoride are as follows.
No. of moles = 
= 
= 0.268 mol
Now, using the ideal gas equation we will find the pressure as follows.
PV = nRT
P = 0.139 atm
Thus, we can conclude that pressure of chlorine pentafluoride gas in the given reaction vessel after the reaction is 0.139 atm.
