Answer:
Some of the physical changes used by the industrial chemist in order to identify it is by scratching it with other metals in order to find the hardness of it. Trying to deform it in order to find the malleability, and to heat it and measure the temperature in order to find the melting point.
Some of the chemical changes used by the industrial chemist in order to identify it is by inserting it in water to observe that whether it reacts with it or not, if the reaction is violent, then the metal belongs to either group I or group II. The other method is to insert it in acids of distinct strength and to observe its reaction. The metals belonging to the second group react briskly with acids. The other metals react gradually with acids and others are almost inert.
Answer:
ΔG° = -5.4 kJ/mol
ΔG = 873.2 J/mol = 0.873 kJ /mol
Explanation:
Step 1: Data given
ΔG (NO2) = 51.84 kJ/mol
ΔG (N2O4) = 98.28 kJ/mol
Step 2:
ΔG = ΔG° + RT ln Q
⇒with Q = the reaction quatient
⇒with T = the temperature = 298 K
⇒with R = 8.314 J / mol*K
⇒with ΔG° = ΔG° (N2O4) - 2*ΔG°(NO2
)
⇒ ΔG° = 98.28 kJ/mol - 2* 51.84 kJ/mol
⇒ ΔG° = -5.4 kJ/mol
Part B
ΔG = ΔG° =RT ln Q
⇒with G° = -5.4 kj/mol = -5400 j/mol
⇒
with R = 8.314 J/K*mol
⇒with T = 298 K
⇒with Q = p(N2O4)/ [ p(NO2) ]² = 1.63/0.36² = 12.577
ΔG = -5400 + 8.314 * 298 * ln(12.577)
ΔG = -5400 + 8.314 * 298 * 2.532
ΔG = 873.2 J/mol = 0.873 kJ/mol
Answer:
i thin its a solution with the pH of 3
Explanation:
i don't understand the third choice
Answer:
Option 6 ) Neutralization
Explanation:
For this case, the missing coefficient would be a "6" before the H₂O, within final products (right side of the equiation), hence, the final reaction should be:
2H₃PO₄ + 3Ba(OH)₂ ------> Ba₃(PO₄)₂ + 6H₂O
You should have in mind that the amount of atoms at each side of the chemical equation should be the same, so as to comply with the principle of mass conservation. If you add "6" on the left side of the H₂O, the equation will be balanced (for each side, lef and right, you will have: 12H, 2P, 14O and 3Ba)
Lastly, this is a chemical neutralization reaction, where an acid (H₃PO₄) is reacting with a base (Ba(OH)₂) in order to finally obtain a neutral salt (Ba₃(PO₄)₂) and water (H₂O)
Answer:
B. use a new pair of gloves for each piece of evidence
Explanation:
When it comes to the basic precautions of handling biological evidence samples, one has to prevent cross contamination. This refers to the<em> transfer of DNA from one evidence to another evidence</em>; thus, it is important for Jane to use a new pair of gloves for each piece of evidence in order to prevent such occurrence.
Wearing of gloves will also <em>prevent Jane's DNA from being implanted into the sample</em>, and it will keep her safe from contracting blood-borne pathogens like those in the saliva, blood or semen.
