Yes. Percent yield shows how efficient one's method is. If his isolated caffeine proved to be at only 1.5%, compared to least 50% as in many of the previous experiments, the student should be very concerned as it shows that something caused the yield to sharply drop.
Answer:
Louis-Bernard Guyton De Morveau
Explanation:
He is who proposed the first systematic nomenclature for naming chemical compounds.
The heat (Q) required to raise the temp of a substance is:<span>Q=m∗Cp∗ΔT</span><span> where m is the mass of the object (25.0g in this case), Cp is the specific heat capacity of the substance (for water Cp = 1.00cal/gC, or 4.18J/gC,
and Dt is the change in temp.
You'll have to solve this twice, once with the Cp in calories, and once with the Cp in joules.
</span><span>1380.72 Joules</span>
Answer:
Explanation:
Molar mass of Ca(Cn)2 = 92. 11 mol/g
Answer: Option D is correct.
Explanation: Equation given by de Broglie is:

where,
= wavelength of the particle
h = Planck's constant
m = mass of the particle
v = velocity of the particle
In option A, football will have some mass and is moving with a velocity of 25 m/s, hence it will have some wavelength.
In Option B, unladen swallow also have some mass and is moving with a velocity of 38 km/hr, hence it will also have some wavelength.
In Option C, a person has some mass and is running with a velocity of 7 m/hr, hence it will also have some wavelength.
As, the momentum of these particles are large, therefore the wavelength will be of small magnitude and hence, is not observable.
From the above, it is clearly visible that all the options are having some wavelength, so option D is correct.