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>
To calculate the amount of heat transferred when an amount of reactant is decomposed, we must look at the balanced reaction and its corresponding heat of reaction. In this case, we can see that 252.8 kJ of heat is transferred per 2 moles of CH3OH used. When 22 g of CH3OH is used, 86.9 kJ is absorbed.
1.01 x 10^24 molecules.
Explanation:
To calculate the number of molecules in a given number of mole, we can simply multiply by Avogadro's number which is equal to 6.022 x 10 ^23.
Therefore,
10 molecules = 1.68 mol x (6.022 x 10^23 molecules) / (1 mol = 1.01 x 10^24) molecules.
I hope this helps :)
Answer: a bench made of composite plastic
Explanation:
The chemical weathering can be defined as the process in which a chemical causes the degradation and decomposition of the rocks into small particles. The iron rods, feldspar, and marble will weather considerably with a greater danger as the have a strong solid body. But plastic when exposed to a chemical agent usually melts and thus there is least or no danger of chemical weathering of plastic.
Answer:
Na₂SO₃
Explanation:
We can use the <em>criss-cross method</em> to work out the formula.
1. Write the <em>symbols</em> of the anion and cation.
Na¹⁺ SO₃²⁻
2. <em>Criss-cross the numbers of the charge</em>s to become the subscripts of the other ion (see image).
3. Write the formula with the <em>new subscripts</em>.
Na₂(SO₃)₁
4. Omit all subscripts <em>that are 1.</em>
The formula becomes Na₂SO₃.
