Answer:
All of the above are true
Explanation:
a) The emission spectrum of a particular element is always the same and can be used to identify the element: It's true since the emission spectrum for each element is unique. It has the same bright lines at the same wavelength. This feature is used to identify elements. For example, the study of the emission spectra of light arriving from stars allow us to identify the elements presents in the star because the light contains the emission spectra of those elements.
b)The uncertainty principle states that we can never know both the exact location and speed of an electron: It is true since the velocity of an electron is related to its wave nature, while its position is related to its particle nature and we cannot simultaneously measure electron's position and velocity with precision.
c) An orbital is the volume in which we are most likely to find an electron: An orbital is a probability distribution map that is used to decribe the likely position of an electron in an atom.
Answer:- 13.6 L
Solution:- Volume of hydrogen gas at 58.7 Kpa is given as 23.5 L. It asks to calculate the volume of hydrogen gas at STP that is standard temperature and pressure. Since the problem does not talk about the original temperature so we would assume the constant temperature. So, it is Boyle's law.
Standard pressure is 1 atm that is 101.325 Kpa.
Boyle's law equation is:

From given information:-
= 58.7 Kpa
= 23.5 L
= 101.325 Kpa
= ?
Let's plug in the values and solve it for final volume.

On rearranging the equation for 

= 13.6 L
So, the volume of hydrogen gas at STP for the given information is 13.6 L.
Answer:
THE HEAT NEEDED TO CHANGE 3KG OF WATER FROM 10 C TO 80 C IS 877.8kJ OR 877,800 J.
Explanation:
Mass = 3.0 kg = 3 * 1000 = 3000 g
Initial temperature = 10 C
Final temperature = 80 C
Change in temperature = 80 - 10 = 70 C
Specific heat of water = 4.18 J/g C
Heat needed = unknown
Heat is the amount of energy in joules needed to change a gram of water by 1 C.
Heat = mass * specific heat * change in temperature
Heat = 3000 g * 4.18 J/g C * 70 C
Heat = 877 800 Joules
Heat = 877.8 kJ.
The heat needed to change 3 kg mass of water from 10 C to 80 C is 877,800 J or 877.8 kJ.
In Grignard reaction, Biphenyl and benzene are common side products which are removed during trituration.
In organic chemistry, a reaction in which the Grignard reagents or organometallic substances are added to organic compounds such as aldehydes and ketones to form alcohol is known as Grignard reaction.
These Grignard reagents are magnesium halides of alkyl, vinyl or allyl, which react with a carbonyl group to form alcohols.
During this reaction, primary, secondary and tertiary alcohols are formed.
While Biphenyl and benzene are common side products.
These are removed during trituration process in which cold petroleum ether is added to dissolve the biphenyl and benzene side products
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