Answer:
Helium and also nitrogen
Explanation:
Helium, as well as nitrogen, can be used for storage of a fresh sample of an oil for a long time because they prevent the oil from rancidity. The contact of air and oil is prevented by using nitrogen or helium as blanketing gas.
Answer:
is that in a molecule of an element, all the atoms are the same. For example, in a molecule of water (a compound), there is one oxygen atom and two hydrogen atoms. But in a molecule of oxygen (an element), both of the atoms are oxygen.
Explanation:
Answer:
607 ppm
Explanation:
In this case we can start with the <u>ppm formula</u>:
If we have a solution of <u>0.0320 M</u>, we can say that in 1 L we have 0.032 mol of , because the molarity formula is:
In other words:
If we use the <u>atomic mass</u> of (19 g/mol) we can convert from mol to g:
Now we can <u>convert from g to mg</u> (1 g= 1000 mg), so:
Finally we can <u>divide by 1 L</u> to find the ppm:
<u>We will have a concentration of 607 ppm.</u>
I hope it helps!
The question is missing the table. Here is the complete question.
The tableshows the concentration of a reactant in the mixture over a period of time.
Reactant Concentration
Time (s) Concentration (M)
0 1.8
210 1.2
450 0.8
580 0.6
720 0.4
What is the average rate of reaction over the first 450 seconds?
A. 1.6x M
B. 1.9x M
C. 2.0x M
D. 2.2x M
Answer: D. 2.2x M
Explanation: The average rate of a reaction is the rate of change of the concentrations (of reactants or products) in a period of time:
average = - ΔC/Δt
In this case, concentration is negative because it's related to reactant, since its concentration dimishes while the concentration of product increases.
For the first 450 seconds:
Average =
Average =
Average = 0.0022
or
Average = 2.2x
So, <u>the Average Rate of the reaction is 2.2x</u><u>M</u>
Covalent compounds are those which are made up by sharing of electrons between them and the electronegativity of the elements which form covalent compounds are nearly same that is they are generally non-polar in nature whereas ionic compounds are formed by complete transfer of electrons from one element to the other and thus resulting in formation of ions of opposite charges that is cation (with positive charge) and anion (with negative charge). There is a large difference in electronegativity of the element involved in the formation of ionic compounds. They are held together by electrostatic force of attraction between them.
The conductivity of a substance is determined by the flow of electric charge. When the charged particles move that are present in the ionic compounds only in the conductivity apparatus they complete the circuit by the flow of electrons.
Hence, a conductivity apparatus test whether a solution has ionic or covalent substances in it as ions complete the flow of electrons to form a circuit.