Answer:
Independent: sizes of nails
Dependent: number of paper clips
Controlled: Battery, wire and type of nails
Explanation:
An independent variable is a variable which when changes does not the effect the results of the experiment. It does not depends upon the dependent variable.
A dependent variable is defined as a variable which is affected when the independent variable is changed by the researcher or the experimenter. It depends greatly upon the independent variable.
While a controlled variable is that variable whose value is not changed in an experiment. It contains all the constants.
In the context,
the independent variable are : sizes of nails
the dependent variables are : number of paper clips
the Controlled variables are: Battery, wire and type of nails
Answer:
Here's what I get
Explanation:
You may have done a Williamson synthesis of guaifenesin by reacting guaiacol with 3-chloropropane-1,2-diol.
A. Mechanism
Step 1
NaOH converts guaiacol into a phenoxide ion.
Step 2
The phenoxide acts as the nucleophile in an SN2 reaction to displace the Cl from the alkyl halide.
B. Improve the yield
You probably carried out the reaction in ethanol solution — a polar protic solvent.
You might try doing the reaction in a polar aprotic solvent— perhaps DMSO.
A polar aprotic solvent does not hydrogen bond to nucleophiles, so they become stronger.
C. Another method of ether synthesis —dehydration of alcohols
Sulfuric acid catalyzes the conversion of primary alcohols to ethers.
This is also a nucleophilic displacement reaction.
Protonation of the OH converts it into a better leaving group.
Attack by a second molecule of alcohol forms the protonated ether.
A molecule of water then removes the proton.
Answer:
w = -531 kJ
1. Work was done by the system.
Explanation:
Step 1: Given data
- Heat gained by the system (q): 687 kJ (By convention, when the system absorbs heat, q > 0).
- Change in the internal energy of the system (ΔU°): 156 kJ
Step 2: Calculate the work done (w)
We will use the following expression.
ΔU° = q + w
w = ΔU° - q
w = 156 kJ - 687 kJ
w = -531 kJ
By convention, when w < 0, work is done by the system on the surroundings.
Answer: 318 K
Explanation:
Combined gas law is the combination of Boyle's law, Charles's law and Gay-Lussac's law.
The combined gas equation is,
where,
= initial pressure of gas = 231 kPa
= final pressure of gas = 168 kPa
= initial volume of gas = 3.25 L
= final volume of gas = 4.35 L
= initial temperature of gas = 
= final temperature of gas = ?
Now put all the given values in the above equation, we get:
At 318 K of temperature will the same gas take up 4.35 liters of space and have a pressure of 168 kPa
Ice, water, fog/water vapor
