Answer:
D. Gases were released to the atmosphere
Explanation:
In accordance to the law of conservation of mass, the total amount of reactants must equate the total amount of products at the end of the reaction because matter can not be lost or created. However, certain changes like gas evolution, formation of precipitate etc. indicates the occurrence of a chemical reaction.
In a chemical reaction, the total mass of the product(s) would be less than the total weight of the reactant(s) because GASES, which constituted part of the mass of the reaction, WERE RELEASED INTO THE ATMOSPHERE. However, if the mass of the gas released can be accounted for, the amount of reactants and products must balance.
Answer:
Final temperature = T₂ = 155.43 °C
Explanation:
Specific heat capacity:
It is the amount of heat required to raise the temperature of one gram of substance by one degree.
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
Given data:
Mass of coin = 4.50 g
Heat absorbed = 54 cal
Initial temperature = 25 °C
Specific heat of copper = 0.092 cal/g °C
Final temperature = ?
Solution:
Q = m.c. ΔT
ΔT = T₂ -T₁
Q = m.c. T₂ -T₁
54 cal = 4.50 g × 0.092 cal/g °C × T₂ -25 °C
54 cal = 0.414 cal/ °C × T₂ -25 °C
54 cal /0.414 cal/ °C = T₂ -25 °C
130.43 °C = T₂ -25 °C
130.43 °C + 25 °C = T₂
155.43 °C = T₂
Here we have to draw the four isomers of the compound 3-bromo-4-fluorohexane.
The four isomers of the compound is shown in the figure.
In an organic molecule the chiral -C center is that where four (4) different groups are present. In 3-bromo-4-fluorohexane the 3 and 4 positions are chiral centers. The possible isomers of a molecule can be obtained from the formula 2n. As here 2 chiral centers are present thus number of stereoisomers will be 2×2 = 4.
The four different isomers as shown in the figure are 3R-, 4R-; 3S-, 4S; 3R, 4S and 3S-, 4R- 3-bromo-4-fluorohexane.
In the 3-bromo-4-fluorohexane the functional groups are -Br, C₂H₅, -C₃H₆F and -H for 3-position and -F, -C₂H₅, -C₃H₆ and -H for 4-position respectively.
The priority of the -3 position will be Br > C₃H₆F > C₂H₅ > H and for -4 position F > C₃H₆Br > C₂H₅ > H. If the rotation from the higher priority group to lower is clockwise and anticlockwise then the S- and R- notation are used respectively. However if the -H atom is present at the horizontal position then the notation will be reverse.
Thus the four isomers of the compound is shown.
The method that can be used to separate the mixture is chromatography.
<h3>
What is chromatography?</h3>
"Chromatography" is obtained form a Greek word which literarily means, color writing. It is a method of separation which is common in separating a mixture of pigments.
To obtain the colors used, two solvents are mixed and the sample ink is dissolved in the solvents then spotted on a thin layer and put into a TLC chamber then the chromatogram is allowed to develop.
The various components of the pigment will appear on the chromatogram and can be identified using spectrophotometry. The Rf values of each component can also be used to identify it.'
Learn more about chromatography: brainly.com/question/26491567
Explanation:
Start with a balanced equation.
2H2 + O2 → 2H2O
Assuming that H2 is in excess, multiply the given moles H2O by the mole ratio between O2 and H2O in the balanced equation so that moles H2O cancel.
5 mol H2O × (1 mol O2/2 mol H2O) = 2.5 mol O2
Answer: 2.5 mol O2 are needed to make 5 mol H2O, assuming H2 is in excess.
