Answer:
From the periodic table:
mass of carbon = 12 grams
mass of hydrogen = 1 grams
mass of oxygen = 16 grams
molar mass of surcose = 12(12) + 22(1) + 11(16) = 342 grams
number of molecules = number of moles x Avogadro's number
number of moles = number of molecules / Avogadro's number
number of moles = (2.2x10^17) / (6.02x10^23) = 3.6544 x 10^-7 moles
number of moles = mass / molar mass
mass = number of moles x molar mass
= 1.7 x 10^17/6.022 x 10^23.
Answer:
So first thing to do in these types of problems is write out your chemical reaction and balance it:
Mg + O2 --> MgO
Then you need to start thinking about moles of Magnesium for moles of Magnesium Oxide. Based on the above equation 1 mole of Magnesium is needed to make one mole of Magnesium Oxide.
To get moles of magnesium you need to take the grams you started with (.418) and convert to moles by dividing by molecular weight of Mg (24.305), this gives you .0172 moles of Mg.
The theoretical yield would be the assumption that 100% of the magnesium will be converted into Magnesium Oxide, so you would get, based on the first equation, .0172 mol of MgO. Multiplying this by the molecular weight of MgO (24.305+16) gives us .693 g of MgO.
The percent yield is what you actually got in the experiment, and for this you subtract off the total mass from the crucible mass, or 27.374 - 26.687, which gives .66 g of MgO obtained.
Percent yield is acutal/theoretical, .66/.693, or 95.24%.
I'll let you do the same for the second trial, and average percent yield is just an average of the two trials percent yield.
Hope this helps.
Explanation:
What benzene is
Benzene is a chemical that is a colorless or light yellow liquid at room temperature. It has a sweet odor and is highly flammable.
Benzene evaporates into the air very quickly. Its vapor is heavier than air and may sink into low-lying areas.
Benzene dissolves only slightly in water and will float on top of water.
I believe the correct answer from the choices listed above is option D. The action that leads to crystal formation in minerals is that atoms or molecules form repeating patterns. Minerals are known to have a crystalline structure in which they exhibit short range and long range patterns.
Answer:
0.278 mol HCl
Explanation:
We currently have 185.0 mL of a 1.50 mol/L solution of HCl. We want to find the number of moles there are.
Based on the given information, our volume is 185.0 mL and our molarity is 1.50. Because molarity is defined as moles / Litre, we can easily find the moles given volume by multiplying molarity by volume.
First, though, we must convert millilitres to litres. There are 1000 mL in 1 L, so divide 185.0 by 1000:
185.0 / 1000 = 0.185 L
Now, multiply 0.185 by 1.50:
0.185 L * 1.50 mol/L = 0.278 mol HCl
Thus the answer is 0.278 mol HCl.
<em>~ an aesthetics lover</em>
