A physical change alter a given material without changing its chemical
Air is a mixture and table salt is a compound. Air is composed of different types of elements that can be separated whereas table salt is more uniform and consists of Na (sodium) and Cl (chloride) to form the compound sodium chloride.
Answer:
1. Dmitri Mendeleev
2. Johann Dobhereiner
3. John Newlands
4. Henry Moseley
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Answer:
668.9K is the final temperature
Explanation:
The change in entropy, ΔS, of an ideal monoatomic gas is obtained using the equation:
ΔS = n*Cv*ln (T2/T1)
<em>Where ΔS is change in entropy = 200J/K</em>
<em>n are moles = 20.0mol</em>
Cv is 3/2R for an ideal monoatomic gas (3/2*8.314J/molK)
T2 is final Temperature and T1 initial temperature = 300K
Replacing:
ΔS = n*Cv*ln (T2/T1)
200J/K = 20.0mol*3/2 *8.314J/molK*ln (T2/300K)
0.80186 = ln (T2/300K)
2.23 = T2 / 300K
<h3>668.9K is the final temperature</h3>
Answer:
Refluxing allows thermally unstable reactants to react faster without decomposition.
Explanation:
Reflux is an experimental laboratory technique, used to produce heating reactions that take place at temperatures higher than room temperature and where it is better to maintain a constant volume in the reaction. By means of this mechanism, it is possible to avoid losing solvent in the course of the process, and therefore, without releasing it into the atmosphere. This is used to heat mixtures for a long time at a certain temperature. As the temperature increases, the reactant particles collide more times and, because they have more energy, there are more particles that exceed the activation energy, which leads to more effective collisions and a higher reaction speed.