Which of the following conditions will most enhance the spontaneity of a reaction?
\(\Delta\)H is negative and greater than T\(\Delta\)S
\(\Delta\)H is negative and \(\Delta\)S = 0
\(\Delta\)H is positive and less than T\(\Delta\)S
\(\Delta\)H is positive and equal to T\(\Delta\)S
Correct answer is A
No explanation has been provided for this answer.
10g
25g
20g
15g
Correct answer is A
Equation: Ca(HCO\(_3\))\(_2\) \(\to\) CaCO\(_3\) (precipitate) + H\(_2\)O + CO\(_2\) (in the presence of heat)
V = 200 cm\(^3\) = 0.2 dm\(^3\)
C = 0.5 mol/dm\(^3\) = 0.5M
N = CV \(\implies\) N = 0.5 \(\times\) 0.2
= 0.1 mole
From the equation 1 mole of Ca(HCO\(_3\))\(_2\) gives 100g of CaCO\(_3\)
(1 mole CaCO\(_3\) = 40 + 12 + (3 x 16) = 100g\)
0.1 mole of Ca(HCO\(_3\))\(_2\) gives x g of CaCO\(_3\).
\(\frac{1}{0.10} = \frac{100}{x}\)
\(x = 100 \times 0.10 = 10 g\)
addition of water, filtration, evaporation to dryness and sublimation
filtration, evaporation to dryness, addition of water and sublimation
sublimation, filtration, evaporation and addition of water
sublimation, addition of water, filtration and evaporation to dryness
Correct answer is A
Process:
Add water to the mixture and then filter. The resultant is a salt solution as your filtrate and a mixture of iodine and sand as your residue. Evaporate the filtrate to dryness to get your sodium chloride (salt). Heat the residue to sublime the iodine from the sand.
Addition of water \(\to\) Filtration \(\to\) Evaporation \(\to\) Sublimation.
Ca(OH)\(_2\) and NaOH
Na\(_2\)CO\(_3\)
NaCl
NaOH
Correct answer is A
Soda lime is a mixture of caustic soda (NaOH) and lime water (Ca(OH)\(_2\)).
van der waals force
dative bond
ionic bond
a covalent bond
Correct answer is D
Hydrogen bond is a covalent intermolecular bond that exists between hydrogen and highly electronegative elements like nitrogen, oxygen and fluorine.