Answer: The forensic examination of substances involve a preliminary flame test.
Explanation:
The forensic chemical analysis of samples involves the flame testing which is one of the preliminary test. The materials are burned on a flame and the color of the flame is considered indicative of the elements present in the material.
The substances like Borax (sodium borate), Copper(II) sulfate, and boric acid burn with a characteristic green flame.
32.7 g Zn
Explanation:
First convert the amount of gas into moles:
11.2 L H2 × (1 mol H2/22.4 L H2) = 0.500 mol H2
Then use the molar ratio to find the amount of zinc necessary to produce the amount of gas above:
0.500 mol H2 × (1 mol Zn/1 mol H2)
= 0.500 mol Zn
Now use the molar mass of zinc to find the number of grams of zinc for the reaction to occur:
0.500 mol Zn × (65.38 g Zn/1 mol Zn)
= 32.7 g Zn
The density of a sample of nitrogen gas (N₂) that exerts a pressure of 5.30 atm in a 3.50-L container at 125°C is 4.54 gm/litre
<h3>What is the
Ideal Gas Law ?</h3>
This law combines the relationships between p, V, T and mass, and gives a number to the constant.
The ideal gas law is:
pV = nRT
where n is the number of moles, and R is universal gas constant.
The value of R depends on the units involved, but is usually stated with S.I. units as: R = 8.314 J/mol·K
The values given in the question are
p= 5.30 atm , V=3.50 L
T (in Kelvin) = 125+273 K
= 398 K
R = 0.0821 L·atm /mol·K
The Ideal Gas equation can be re written as
pM=DRT
M is the molar mass , D is the density
M for N₂ is 28 gm/mol
so density can be determined as
Therefore the density of a sample of nitrogen gas (N₂) that exerts a pressure of 5.30 atm in a 3.50-L container at 125°C is 4.54 gm/litre
To know more about Ideal Gas Law
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Statement B is true because atoms are single particles that come together to form compounds and molecules.