Answer:
Explanation:
From the equation:
H2SO4(aq) + 2NaOH(aq) --> Na2SO4(aq) + 2H2O (l)
<em>1 mole of the acid (H2SO4) and 2 moles of the base (NaOH) are required for complete neutralization.</em>
mole of acid (H2SO4) present = molarity x volume
= 1 x 0.1 = 0.1 mole
Mole of base (NaOH) present = mass/molar mass
= 7/40 = 0.175 mole
<em>The ratio of acid and base should be 1:2, hence the acid is slightly excessive in this case and the base is the limiting reagent that will determine the extent of the reaction.</em>
Amount of excess acid = 0.1 - 0.175/2
= 0.0125 mole
volume of excess acid = mole/molarity
= 0.0125 x 1 = 0.0125 L
= 12.5 mL
<em>Hence, the acid (H2SO4) was in excess by 12.5 mL.</em>
The absorbance reported by the defective instrument was 0.3933.
Absorbance A = - log₁₀ T
Tm = transmittance measured by spectrophotometer
Tm = 0.44
Absorbance reported in this equipment = -log₁₀ (0.44) = 0.35654
True absorbance can be calculated by true transmittance, Tm = T+S(α-T)
S = fraction of stray light = 6%= 6/100 = 0.06
α= 1, ideal case
T = true transmittance of the sample
Tm = T+S(α-T)
now, T= Tm-S/ 1-S = 0.44-0.06/ 1-0.06 = 0.404233
therefore, actual reading measured is A = -log₁₀ T = -log₁₀ (0.404233)
i.e; 0.3933
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Answer:
Hey there!
Antimony is the element with an atomic number of 51. The element is in group 15, and in period 5.
Let me know if this helps :)
Answer: Correct option is 3.
Explanation: Properties of Acid:
- They are liquids.
- Acids are the ones which donate hydrogen ions to the solution.
- They turn blue litmus paper to red.
- They are corrosive in nature.
- They are sour in taste. For example: vinegar
From the above properties written, it can be said that option 3 is correct.
The amount of heat, H, needed to boil off certain mass, m, of the substance is given by the equation,
H = mHv
where Hv is the heat of vaporization. Manipulating the equation, the mass is calculated by,
m = H/Hv
Substituting the known values,
m = 15000 J/(850 J/g) = 17.65 g
Thus, the mass of ethyl alcohol is approximately 17.65 g.
