Answer:
A = 8
B = 8
C = Oxygen (O)
D = 26
E = 30
F = Iron (Fe)
Explanation:
protons neutrons atomic number mass number element
A 7 B 15 C
D E 26 56 F
mass number = protons + neutrons
E = 56 - 26 = 30
A = 15 - 7 = 8
protons = atomic number
B = 8
D = 26
From atomic number:
C = Oxygen (O)
F = Iron (Fe)
The enthalpy change of the precipitation reaction is 84 kJ/mole
Why?
The chemical equation for the reaction is
AgNO₃(aq) + NaCl (aq) → AgCl(s) + NaNO₃(aq)
To find the enthalpy change we need to apply the following equation

To find the heat (Q):

Now, to find the number of moles that react (n):
![n=[AgNO_3]*v(L)=(0.1M)*(0.05L)=0.005moles](https://tex.z-dn.net/?f=n%3D%5BAgNO_3%5D%2Av%28L%29%3D%280.1M%29%2A%280.05L%29%3D0.005moles)
Having these two values we can plug in the first equation:

Have a nice day!
The
balanced half-reaction: Cr⁴⁺(aq)+ 4e⁻ →
Cr(s).
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Chromium(IV) cations gain four electrons and became solid chromium with neutral charge.
</span>Reduction is lowering oxidation number because element or ions gain electrons.
Oxidation reaction is increasing of oxidation number of element, because
element or ion lost electrons in chemical reaction.
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</span>
The final temperature of the lead-water system will be lower than the final temperature of the copper-water system.
Explanation:
A volatile substance is defined as the substance which can easily evaporate into the atmosphere due to weak intermolecular forces present within its molecules.
Whereas a flammable substance is defined as a substance which is able to catch fire easily when it comes in contact with flame.
Hence, when we heat a flammable or volatile solvent for a recrystallization then it should be kept in mind that should heat the solvent in a stoppered flask to keep vapor away from any open flames so that it won't catch fire.
And, you should ensure that no one else is using an open flame near your experiment.
Thus, we can conclude that following statements are correct:
- You should heat the solvent in a stoppered flask to keep vapor away from any open flames.
- You should ensure that no one else is using an open flame near your experiment.