answer an element and a compound
A technician mixes 80 ml of a 5% solution with 10 ml of water. the final percentage strength of the solution prepared is 40 %.
given that :
8 ml of a 5 % solution mix with 10 ml . that means the 80 mL of 5 % solution is diluted with water of 10 mL
therefore, 80 × 5 = 10 × x %
x % = 40 %
Therefore, the final percentage strength of the solution is 40 %
Thus, A technician mixes 80 ml of a 5% solution with 10 ml of water. the final percentage strength of the solution prepared is 40 %.
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Answer:
0.967mole
Explanation:
Given parameters:
Volume of NH₄Cl = 21.67L
Unknown:
Number of moles = ?
Solution:
If we assume that the volume was taken at standard temperature and pressure,
Then;
Number of moles = 
Number of moles = 
= 0.967mole
91 grams of sodium azide required to decompose and produce 2.104 moles of nitrogen.
Explanation:
2NaN3======2Na+3N2
This is the balanced equation for the decomposition and production of sodium azide required to produce nitrogen.
From the equation:
2 moles of NaNO3 will undergo decomposition to produce 3 moles of nitrogen.
In the question moles of nitrogen produced is given as 2.104 moles
so,
From the stoichiometry,
3N2/2NaN3=2.104/x
= 3/2=2.104/x
3x= 2*2.104
= 1.4 moles
So, 1.4 moles of sodium azide will be required to decompose to produce 2.104 moles of nitrogen.
From the formula
no of moles=mass/atomic mass
mass=no of moles*atomic mass
1.4*65
= 91 grams of sodium azide required to decompose and produce 2.104 moles of nitrogen.
Answer:
See Explanation
Explanation:
1) Let us recall that;
Mass number = number of protons + number of neutrons
Where;
Number of protons = ?
Number of neutrons =20
Mass number =39
Number of protons = mass number - number of neutrons
Mass of protons =39 - 20= 19 protons
2) Atomic number = 13
Number of neutrons =14
Then the mass number =13 +14 =27
The symbol of the element is 27X13
The number of protons= the number of electrons =13
The atomic number is the same as the proton number =13
