JEE Mains · Chemistry · STD 11 - 5. Thermodynamics and thermochemistry
Solid fuel used in rocket is a mixture of \(Fe _2 O _3\) and \(Al\) (in ratio \(1: 2\) ). The heat evolved \(( kJ )\) per gram of the mixture is \(............\). (Neatest integer) Given : \(\Delta H _{ f }^{\ominus}\left( Al _2 O _3\right)=-1700\,kJ\,mol ^{-1}\) \(\Delta H _{ f }^\theta\left( Fe _2 O _3\right)=-840\,kJ\,mol ^{-1}\) Molar mass of \(Fe , Al\) and \(O\) are \(56,27\) and \(16\,g\,mol ^{-1}\) respectively.
- A \(3\)
- B \(2\)
- C \(5\)
- D \(4\)
Answer & Solution
Correct Answer
(D) \(4\)
Step-by-step Solution
Detailed explanation
\(Fe _2 O _3+2 Al \rightarrow Al _2 O _3+2 Fe\) Molar mass \(160\,g \quad 27\,g\) \(\left(\Delta H _{ f }^0\right)_{\text {reaction }}=\left[\left(\Delta H _{ f }^0\right)_{ Al _2 O _3}+2\left(\Delta H _{ f }^0\right)_{ Fe }\right]\)…
See the Complete Solution
Get step-by-step explanations for this and 2.5 Lakh+ more JEE, NEET & CET questions.
- Unlock all solutions
- Practice the full chapter
- Track accuracy across PYQs
4.8 rated on Google Play · 14,000+ reviews
More questions from Chemistry
- \(t_{100\%}\) is the time required for the \(100\%\) completion of the reaction while \(t_{1/2}\) is the time required for \(50\%\) of the reaction to be completed. Which of the following option correctly represents the relation between \(t_{100\%}\) and \(t_{1/2}\) for zero and first order reactions respectively?JEE Mains 2026 Medium
- During the nuclear explosion, one of the products is \(^{90} \mathrm{Sr}\) with half life of \(6.93\) years. if \(1 \;\mu g\) of \(^{90} \mathrm{Sr}\) was absorbed in the bones of a newly born baby in place of \(Ca\), how much time, in years, is required to reduce it by \(90 \%\) if it is not lost metabolicallyJEE Mains 2020 Hard
- During the borax bead test with \(CuSO _4\), a blue green colour of the bead was observed in oxidising flame due to the formation ofJEE Mains 2023 Hard
- The ratio \(\frac{{{K_p}}}{{{K_c}}}\) for the reaction \(CO\left( g \right) + \frac{1}{2}{O_2}\left( g \right) \rightleftharpoons C{O_2}\left( g \right)\) isJEE Mains 2013 Hard
- The number of incorrect statements from the following is \(A.\) The electrical work that a reaction can perform at constant pressure and temperature is equal to the reaction Gibbs energy. \(B.\) \(E _{\text {cell }}^0\) is dependent on the pressure \(C.\) \(\frac{ dE ^0 \text { cell }}{ dT }=\frac{\Delta_{ r } S ^0}{ nF }\) \(D.\) A cell is operating reversibly if the cell potential is exactly balanced by an opposing source of potential difference.JEE Mains 2023 Hard
- Among the following the set of parameters that represents path functions, is \((a)\,\,q + w\) \( (b)\,\,q\) \((c)\,\,w\) \( (d)\,\,H -TS\)JEE Mains 2019 Hard
More PYQs from JEE Mains
- The coefficient of \(x^{48}\) in \((1+x)+2(1+x)^{2}+3(1+x)^{3}+....+100(1+x)^{100}\) is equal to:JEE Mains 2026 Medium
- Let \(a_1, a_2, \ldots . a_{10}\) be \(10\) observations such that \(\sum_{\mathrm{k}=1}^{10} \mathrm{a}_{\mathrm{k}}=50\) and \(\sum_{\forall \mathrm{k}<\mathrm{j}} \mathrm{a}_{\mathrm{k}} \cdot \mathrm{a}_{\mathrm{j}}=1100\). Then the standard deviation of \(a_1, a_2, \ldots, a_{10}\) is equal to :JEE Mains 2024 Hard
- A parallel plate capacitor has charge \(5 \times 10^{-6} \mathrm{C}\). A dielectric slab is inserted between the plates and almost fills the space between the plates. If the induced charge on one face of the slab is \(4 \times 10^{-6} \mathrm{C}\) then the dielectric constant of the slab is ________.JEE Mains 2025 Medium
- The oxidation states of nitrogen in \(NO , NO _{2}, N _{2} O\) and \(NO _{3}^{-}\) are in the order of :JEE Mains 2021 Medium
- If \(\displaystyle\int_{\pi/6}^{\pi/4}\left(\cot\left(x-\dfrac{\pi}{3}\right)\cot\left(x+\dfrac{\pi}{3}\right)+1\right)dx = \alpha\log_e(\sqrt{3}-1)\), then \(9\alpha^2\) is equal to ________.JEE Mains 2026 Hard
- Let \(\vec{a}=-\hat{i}-\hat{j}+\hat{k}, \vec{a} \cdot \vec{b}=1\) and \(\vec{a} \times \vec{b}=\hat{i}-\hat{j}\). Then \(\vec{a}-6 \vec{b}\) is equal toJEE Mains 2023 Medium