Answer:
The standard enthalpy of formation of HgO is -90.7 kJ/mol.
Explanation:
The reaction between Hg and oxygen is as follows.
From the given,
Molar mass of HgO = 216.59 g/mol
Mass of HgO decomposed = 18.5 g
Amount of heat absorbed = 7.75 kJ
From the reaction,
The standard enthalpy of formation = 
During the decomposition of 1 mol of HgO , 90.7 kJ of energy absorbed.
For the formation of 1 mol of HgO , 90.7 kJ of energy is release
Therefore, the enthalpy of formation of mercury(II)Oxide is -90.7 kJ/mol
The preparation of lead (ii) sulphate from lead (ii) carbonate occurs in two steps:
- insoluble lead carbonate is converted to soluble lead (ii) nitrate
- soluble lead (ii) nitrate is reacted with sulphuric acid to produce lead (ii) sulphate.
<h3>How can a solid sample of lead (ii) sulphate be prepared from lead (ii) carbonate?</h3>
Lead (ii) carbonate and lead (ii) sulphate are both insoluble salts of lead.
In order to prepare lead (ii) sulphate, a two step process is performed.
In the first step, Lead (ii) carbonate is reacted with dilute trioxonitrate (v) acid to produce lead (ii) nitrate.
- PbCO₃ + 2HNO₃ → Pb(NO₃)₂ + CO₂ + H₂O
In the second step, dilute sulfuric acid is reacted with the lead (ii) nitrate to produce insoluble lead (ii) sulphate which is filtered and dried.
- Pb(NO₃)₂ + H₂SO₄ → PbSO₄ + 2HNO₃
In conclusion, lead (ii) sulphate is prepared in two steps.
Learn more about lead (ii) sulphate at: brainly.com/question/188055
#SPJ1
Answer:
1.87x10⁻³ M SO₄²⁻
Explanation:
The reaction of SO₄²⁻ with Ba²⁺ (From Ba(NO₃)₂) is:
SO₄²⁻(aq) + Ba²⁺(aq) → BaSO₄(s)
<em>Where 1 mole of SO₄²⁻ reacts per mole of Ba²⁺</em>
<em />
To reach the end point in this titration, we need to add the same moles of Ba²⁺ that the moles that are of SO₄²⁻.
Thus, to find molarity of SO₄²⁻ we need to find first the moles of Ba²⁺ added (That will be the same of SO₄²⁻). And as the volume of the initial sample was 100mL we can find molarity (As ratio of moles of SO₄²⁻ per liter of solution).
<em>Moles Ba²⁺:</em>
7.48mL = 7.48x10⁻³L ₓ (0.0250moles / L) = 1.87x10⁻⁴ moles of Ba²⁺ = Moles of SO₄²⁻
<em>Molarity SO₄²⁻:</em>
As there are 1.87x10⁻⁴ moles of SO₄²⁻ in 100mL = 0.1L, molarity is:
1.87x10⁻⁴ moles of SO₄²⁻ / 0.1L =
<h3> 1.87x10⁻³ M SO₄²⁻</h3>
Answer:
a solid forms, and there is a change of color.
Explanation:
Answer:
E) Intramolecular bond angles change
Explanation:
Infrared Radiation:
IR is electromagnetic radiations. The wavelength i.e. 700nm to 1000 mm of infrared is longer than invisible light and Its frequency is lower than light, that's why it is invisible to light.
- When IR radiation strike the molecule it absorbed by this molecule.
- This radiation used to identify and study chemicals.
- Infrared radiation interact with intra-bonds of the molecule.
- Bonds in the molecules have vibrational translational and rotational movements
- Due to these vibration, rotation and translation movement it absorb a radiation of specific frequency and wavelength
- These movements of bond are very small and absorbs radiations of very low frequency
- So when Infrared light or radiation absorbed the intra-bonds of the molecule get affected and angles of these bonds changes.
- As the frequency of the absorbed radiation matches the frequency of the bond that vibrates.
So
The correct option is option E
E) Intramolecular bond angles change
* Note:
it couldn't be option A as the frequency of IR is not enough to rotate a whole molecule
It Couldn't be option B as IR rations are electromagnetic radiation of longer wave length so it one can not see it with light so how it will glow a molecule
It also not could be the option C as for the excitation of electrons require much higher energy.
It also not the option D as nuclear magnetic spin is associated with nuclear magnetic radiation that are much different from IR.
