Answer:
H₂O + CO₂ → H₂CO₃
Option D is correct.
Law of conservation of mass:
According to this law, mass can neither be created nor destroyed in a chemical equation.
This law was given by French chemist Antoine Lavoisier in 1789. According to this law mass of reactant and mass of product must be equal, because masses are not created or destroyed in a chemical reaction.
Now we will apply this law to given chemical equations:
A) H₂ + O₂ → H₂O
There are two H and two O atoms present on left side while on right side only one O and two H atoms are present so mass in not conserved. This option is incorrect.
B) Mg + HCl → H₂ + MgCl₂
In this equation one Mg, one H and one Cl atoms are present on left side of equation while on right side two H, one Mg and two chlorine atoms are present. This equation also not follow the law of conservation of mass.
C) KClO₃ → KCl + O₂
There are one K, one Cl and three O atoms are present on left side of equation while on right side one K one Cl and two oxygen atoms are present. This equation also not following the law of conservation of mass.
D) H₂O + CO₂ → H₂CO₃
There are two hydrogen, one carbon and three oxygen atoms are present on both side of equation thus, mass remain conserved. This option is correct.
First find the oxidation states of the various atoms:
<span>in Cr2O2 2- Cr @ +1; In NH3 N @ +3; in CrO3 Cr @ +3, N2 N @ 0 </span>
<span>Note that N gained electrons, ie, was reduced; Cr was oxidized </span>
<span>Now there is a problem, because B has NH4+ which the problem did not, and is not balanced, showing e- in/out </span>
<span>B.NH4+ → N2 </span>
<span>Which of the following is an oxidation half-reaction? </span>
<span>A.Sn 2+ →Sn 4+ + 2e- </span>
<span>Sn lost electrons so it got oxidized</span>
Among all of the choices listed, the only option that is a base would be the last one. As it is unique, whereby Hydrogen is not present in the front of the compound.
Bases also possess OH in their molecular formula.
The <span>modern-day quantum model of the atom known as the wave mechanical model depicts that the </span>electron was a three dimensional wave circling the nucleus in a whole number of
wavelengths allowing the waveform to repeat itself as a stable standing wave
(it can absorb energy form a nearby source which is oscillating at a proper
frequency) representing the energy levels of Bohr model.
Yes , the chemist can answer if the compound in K2O or K2O2
The chemical formula and composition of both the compounds is entirely different. The compound K2O2 has an additional molecule of oxygen than K2O and hence will have have higher molecular mass.
In the compound K2O
molecular mass= 2x 39+16 =94
mass ratio of K in compound= 78/94 = 0.830
In the compound K2O2
molecular mass= 2x 39+16X2 =110
mass ratio of K in compound= 78/110 = 0.710
and hence by the required ratio while extracting K , the chemist may know if the compound is K20 or K2O2
If the ratio is anything different from 0.830 and 0.710 then the compund will be something different
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