The correct answer would be the last option. A double displacement type of reaction involves the switching of places the cations and anions accordingly. The given reaction is erroneous since in the product side the anions and cations are being paired which would not make sense. The correct reaction should be
4NaBr + Co(SO3)2 yields <span>CoBr4 + 2Na2SO3</span>
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the answer is 43.129310000000004
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Answer:
3) NaCl.
Explanation:
<em>∵ ΔTf = iKf.m</em>
where, <em>i</em> is the van 't Hoff factor.
<em>Kf </em>is the molal depression freezing constant.
<em>m</em> is the molality of the solute.
<em>The van 't Hoff factor is the ratio between the actual concentration of particles produced when the substance is dissolved and the concentration of a substance as calculated from its mass. </em>
<em></em>
- For most non-electrolytes dissolved in water, the van 't Hoff factor is essentially 1.
<em>So, for sugar: i = 1.</em>
<em>∴ ΔTf for sugar = iKf.m = (1)(Kf)(2.0 m) = 2 Kf.</em>
<em></em>
- For most ionic compounds dissolved in water, the van 't Hoff factor is equal to the number of discrete ions in a formula unit of the substance.
For NaCl, it is electrolyte compound which dissociates to Na⁺ and Cl⁻.
<em>So, i for NaCl = 2.</em>
<em>∴ ΔTf for NaCl = iKf.m = (2)(Kf)(1.0 m) = 2 Kf.</em>
<em></em>
<em>So, the right choice is: 3) NaCl.</em>
<em></em>
Answer:
Heating this gas to 55 °C will raise its volume to 6.87 liters.
Assumption: this gas is ideal.
Explanation:
By Charles's Law, under constant pressure the volume
of an ideal gas is proportional to its absolute temperature
(the one in degrees Kelvins.)
Alternatively, consider the ideal gas law:
.
is the number of moles of particles in this gas.
should be constant as long as the container does not leak.
is the ideal gas constant.
is the pressure on the gas. The question states that the pressure on this gas is constant.
Therefore the volume of the gas is proportional to its absolute temperature.
Either way,
.
.
For the gas in this question:
- Initial volume:
.
Convert the two temperatures to degrees Kelvins:
- Initial temperature:
. - Final temperature:
.
Apply Charles's Law:
.
Answer:
NH₄⁺
H₂PO₄⁻
H₃O⁺
Explanation:
- An ion is an atom or molecule with a net electric charge due to the loss or gain of one or more electrons.
- Ion may be positively charged "cation" or negatively charged "anion".
- Neutral molecule has a net charge of zero.
<em>So, the species that are ions are: </em>
NH₄⁺
H₂PO₄⁻
H₃O⁺