A compound is 40.0% c, 6.70% h, and 53.3% o by mass. assume that we have a 100.-g sample of this compound. the molecular formula
1 answer:
<span>When you have 100 g of compound, then based on the percentages given, there are 40.0 g C, 6.70 g H, and 53.3 g O. Convert those to moles:
</span>C: 40.0 g / 12.0 = 3.33 moles of C
<span>H: 6.70 g / 1.01 = 6.63 moles of H </span>
<span>O: 53.3 / 16.0 = 3.33 moles of O
</span>
<span>Dividing by the smallest (3.33), we get a C:H:O mole ratio of 1:2:1
</span>So, <span>The empirical formula is CH2O.
Now, </span><span>That formula has a molar mass of [12.0 + 2(1.0) + 16.0] = 30.0
And we are given it's molar mass is = 240
So, no. of units of CH2O = 240 / 30 = 8
</span><span>8 x CH2O = C8H16O8, and that is the molecular formula.
</span>
</span>C: 40.0 g / 12.0 = 3.33 moles of C
<span>H: 6.70 g / 1.01 = 6.63 moles of H </span>
<span>O: 53.3 / 16.0 = 3.33 moles of O
</span>
<span>Dividing by the smallest (3.33), we get a C:H:O mole ratio of 1:2:1
</span>So, <span>The empirical formula is CH2O.
Now, </span><span>That formula has a molar mass of [12.0 + 2(1.0) + 16.0] = 30.0
And we are given it's molar mass is = 240
So, no. of units of CH2O = 240 / 30 = 8
</span><span>8 x CH2O = C8H16O8, and that is the molecular formula.
</span>
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Answer:
1 mole of a gas would occupy 22.4 Liters at 273 K and 1 atm
Explanation:
An ideal gas is a set of atoms or molecules that move freely without interactions. The pressure exerted by the gas is due to the collisions of the molecules with the walls of the container. The ideal gas behavior is at low pressures, that is, at the limit of zero density. At high pressures the molecules interact and intermolecular forces cause the gas to deviate from ideality.
An ideal gas is characterized by three state variables: absolute pressure (P), volume (V), and absolute temperature (T). The relationship between them constitutes the ideal gas law, an equation that relates the three variables if the amount of substance, number of moles n, remains constant and where R is the molar constant of the gases:
P * V = n * R * T
In this case:
- P= 1 atm
- V= 22.4 L
- n= ?
- R= 0.082
- T=273 K
Reemplacing:
1 atm* 22.4 L= n* 0.082 *273 K
Solving:
n= 1 mol
Another way to get the same result is by taking the STP conditions into account.
The STP conditions refer to the standard temperature and pressure. Pressure values at 1 atmosphere and temperature at 0 ° C (or 273 K) are used and are reference values for gases. And in these conditions 1 mole of any gas occupies an approximate volume of 22.4 liters.
<u><em>1 mole of a gas would occupy 22.4 Liters at 273 K and 1 atm</em></u>