Answer:
The answer is a. -277.6 kJ/mol
Explanation:
We have to arrange and sum the given equations to obtain the desired reaction as follows:
3 H₂O(l) + 2 CO₂(g) → 3 O₂(g) + C₂H₅OH(l) ΔH1= (-1) x (-1367 KJ/mol)
2 C(s) + 2 O₂(g)→ 2 CO₂(g) ΔH2= 2 x (-393.5 KJ/mol)
3 H₂(g) + 3/2 O₂(g) → 3 H₂O(l) ΔH3= 3 x (-285.8 KJ/mol)
In the first equation (ΔH1) , we multiply the enthalphy by (-1) because we use the reverse reaction. In the second and third equations (ΔH2 and ΔH3), we multiply by 2 and 3, respectively. Once we sum and cancel the terms that are repeated in both sides of the reactions, we obtain:
3H₂(g) + 2C(s) + ½O₂(g) → C₂H₅OH(l)
The total enthalphy is:
ΔH= ΔH1 + ΔH2 + ΔH3
ΔH= (-1) x (-1367 KJ/mol) + 2 x (-393.5 KJ/mol) + 3 x (-285.8 KJ/mol)
ΔH= -277.4 KJ/mol
The nearest answer between the given options is option a (-277.6 KJ/mol)
Answer: The density of glycerol will be
Explanation:
Density is defined as the mass contained per unit volume.
Given : Mass of glycerol= g
Volume of bromine = 3.25 L=
Putting in the values we get:
Thus density of glycerol will be
The density of glycerol used in cosmetics and soaps is 1.26 g/cm³.
FURTHER EXPLANATION
Density is the measure of the compactness of a material. It is the mass per given volume. This can be expressed mathematically as:
(equation 1)
To solve the problem, we first sort the given in the problem:
mass = 4.10 × 10³ g
volume - 3.25 L
The problem is asking for the density in units of g/cm³ which means that we must first convert the volume from liters to cm³.
Now we can plug in the values of mass and volume into equation 1:
Since the given in the problem both have 3 significant figures, the final answer must also have three significant digits only. Therefore,
The density of glycerol is greater than 1, so when mixed with water it will sink.
LEARN MORE
Keywords: Density, Mass, Volume, Unit Conversion
Answer:
The water solution
Explanation:
Super freezing occurs when energy is quickly withdrawn from a liquid and it cools below the solidification temperature. This phenomenon occurs due to the fact that the cooling is very fast and does not occur the formation of an initial "point" or crystal, which is generally formed to start the freezing. A small crystal formed will attract the molecules nearby, forming a large crystal, that is, the frozen liquid.
The sugar solution should be distilled so that Super Cooling occurs more efficiently than the water solution because the presence of the sugar would create nucleation points and allow the formation of ice crystals. The super cooled water solution turns very quickly into ice, much faster than the sugar solution. It is also possible to supercooled the water after the homogeneous nucleation point, in which case it eventually solidifies into a type of glass.
(2) 2 (4) 4
Answer : The limiting reagent is .
Solution : Given,
Mass of = 4.0 g
Mass of = 8.0 g
Molar mass of = 17 g/mole
Molar mass of = 32 g/mole
First we have to calculate the moles of and .
Now we have to calculate the limiting and excess reagent.
The balanced chemical reaction is,
From the balanced reaction we conclude that
As, 5 mole of react with 4 mole of
So, 0.25 moles of react with moles of
From this we conclude that, is an excess reagent because the given moles are greater than the required moles and is a limiting reagent and it limits the formation of product.
Hence, the limiting reagent is .