<u>Given:</u>
Mass of ice = mass of water = 5.50 kg = 5500 g
Temperature of ice = -20 C
Temperature of water = 75 C
<u>To determine:</u>
Mass of propane required
<u>Explanation:</u>
Heat required to change from ice to water under the specified conditions is:-
q = q(-20 C to 0 C) + q(fusion) + q (0 C to 75 C)
= m*c(ice)*ΔT(ice) + m*ΔHfusion + m*c(water)*ΔT(water)
= 5500[2.10(0-(-20)) + 334 + 4.18(75-0)] = 3792 kJ
The enthalpy change for the combustion of propane is -2220 kJ/mol
Therefore, the number of moles of propane corresponding to the required energy of 3792 kJ = 1 mole * 3792 kJ/2220 kJ = 1.708 moles of propane
Molar mass of propane = 44 g/mol
Mass of propane required = 1.708 moles * 44 g/mol = 75.15 g
Ans: 75.15 grams of propane must be combusted.
Answer:
Pb(NO₃)₂ (aq) + 2NaCl (aq) → PbCl₂ (s) ↓ + 2NaNO₃ (aq)
Explanation:
The reactants are:
Lead(II) nitrate → Pb(NO₃)₂ (aq)
Sodium chloride → NaCl (aq)
The products are:
Lead(II) chloride → PbCl₂ (s)
Sodium nitrate → NaNO₃ (aq)
Salts form nitrate are soluble. The chloride makes a precipitate with the Pb²⁺. The chemical equation for this reaction is:
Pb(NO₃)₂ (aq) + 2NaCl (aq) → PbCl₂ (s) ↓ + 2NaNO₃ (aq)
Answer:-
Neon is a noble gas. Neon with an electronic configuration of 2,8 has 8 electrons in it's outermost shell or valence shell.
According to the Octet theory if an element has eight electrons in it's valence shell then it is stable and does not undergo reaction. Thus Neon does not need to react and can exist freely in nature.
Sodium with an electronic configuration of 2,8,1 has 1 electron in it's valence shell. As per octet rule, it is not stable and it must lose that 1 electron to become stable.
In order to lose that 1 electron sodium must react with other substances. Hence sodium cannot exist freely in nature.
The rate law for the reaction : r=k.[A]²
<h3>Further explanation</h3>
Given
Reaction
A ⟶ B + C
Required
The rate law
Solution
The rate law is a chemical equation that shows the relationship between reaction rate and the concentration / pressure of the reactants
For the second-order reaction it can be:
1. the square of the concentration of one reactant.
![\tt r=k[A]^2](https://tex.z-dn.net/?f=%5Ctt%20r%3Dk%5BA%5D%5E2)
2. the product of the concentrations of two reactants.
![\tt r=k[A][B]](https://tex.z-dn.net/?f=%5Ctt%20r%3Dk%5BA%5D%5BB%5D)
And the reaction should be(for second order) :
2A ⟶ B + C
Thus, for reaction above (reactant consumption rate) :
![\tt r=-\dfrac{\Delta A}{2\Delta t}=k[A]^2](https://tex.z-dn.net/?f=%5Ctt%20r%3D-%5Cdfrac%7B%5CDelta%20A%7D%7B2%5CDelta%20t%7D%3Dk%5BA%5D%5E2)
Answer is: 12 grams of the isotope carbon-12 (¹²C).
The Avogadro’s number is the number of atoms in 12 grams of the isotope carbon-12 (¹²C).
Na is Avogadro number or Avogadro constant (the number of particles, in this example carbon, that are contained in the amount of substance given by one mole).
The Avogadro number has value 6.022·10²³ 1/mol in the International System of Units; Na = 6.022·10²³ 1/mol.
