Answer:
Energy exists in different forms, all of which can be classified as either potential energy or kinetic energy. Potential energy is energy stored in an object due to its position or arrangement. Kinetic energy is energy of an object due to its movement - its motion.
Explanation:
Answer:
the answer i belive is c
Explanation:
A chemical reaction occurs because heat and light are given off.
Explanation:
A property which causes change in chemical composition of a substance is known as a chemical property. For example, reactivity, toxicity, combustion etc.
Whereas a property which causes no change in chemical composition of a substance is known as a physical property. For example, mass, volume, density etc.
Sodium is a very reactive metal and it reacts readily with oxygen, water etc. So, when sodium is added to water then occurrence of an orange flame represents its reactivity.
Thus, based on given observation it can be concluded that chemical reaction takes place when sodium is added to water.
Reaction 2: C (s, graphite) + 2H2 (g) --> CH4 (g) Change in enthalply: -74.9 kJ/mol
Reaction 3: H2 (g) + 2C (s, graphite) + N2 (g) --> 2HCN (g) Change in enthalpy: +270.3 kJ/mol
Include the following:
The numerical answer with correct units.
State which reactions, if any, you had to "Flip".
State which reactions you had to multiply, if any, to get the correct amount of the compound.
The enthalpy for the reaction, ΔH rxn is 255.95 kJ/mol
From the question,
We are to calculate the change in enthalpy for the reaction
CH₄(g) + NH₃(g) → HCN(g) +3H₂(g)
From the given reactions
Reaction 1: N₂(g) + 3H₂(g) → 2NH₃(g) Change in enthalpy: -91.8 kJ/mol
Reaction 2: C(s, graphite) + 2H₂(g) → CH₄(g) Change in enthalply: -74.9 kJ/mol
Reaction 3: H₂(g) +2C(s, graphite) +N₂(g) → 2HCN (g) Change in enthalpy: +270.3 kJ/mol
First, flip reactions 1 and 2 to get reaction 4 and 5 respectively
Reaction 4: 2NH₃(g) → N₂(g) + 3H₂(g) ΔHo : 91.8 kJ/mol
Reaction 5: CH₄(g) → C(s, graphite) + 2H₂(g) ΔHo : 74.9 kJ/mol
Now, multiply reactions 4 and 3 by half (1/2) to get 6 and 7 respectively
Reaction 6: NH₃(g) → ¹/₂N₂(g) + ³/₂H₂(g) ΔHo : 45.9 kJ/mol
Reaction 7: ¹/₂H₂(g) +C(s, graphite) +¹/₂N₂(g) → HCN (g) ΔHo : +135.15 kJ/mol
Now,
Add reactions 5, 6, and 7 together
Reaction 5: CH₄(g) → C(s, graphite) + 2H₂(g) ΔHo : 74.9 kJ/mol
Reaction 6: NH₃(g) → ¹/₂N₂(g) + ³/₂H₂(g) ΔHo : 45.9 kJ/mol
Reaction 7: ¹/₂H₂(g) +C(s, graphite) +¹/₂N₂(g) → HCN(g) ΔHo : +135.15 kJ/mol
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CH₄(g) + NH₃(g) → HCN(g) + 3H₂(g) ΔH rxn = 255.95 kJ/mol
Hence, the enthalpy for the reaction, ΔH rxn is 255.95 kJ/mol
Learn more here: brainly.com/question/13779366
Answer:
255.8 kj/mol
Explanation:
So this is a Hess' Law problem, the CH₄ (g) + NH₃ (g) --> HCN (g) + 3H₂ (g) is what we want the other reactions to reflect. I usually set up problems like these like this in order to determine which reaction needs a coefficient change:
N₂ + 3H₂ --> 2NH₃ (ΔH=-91.8)
C + 2H₂ --> CH₄ (ΔH=-74.9
H₂ + 2C + N₂ --> 2HCN (ΔH=270.3)
CH₄ + NH₃ --> HCN + 3H₂
(I left out the states because it'll make the math easier) So, we want things to cancel out, meaning some of the reactants and products need to change places in order to do so. For the first reaction, we'd want to multiply the coefficients by in order to have it cancel out with the other reactions. For the third reaction, we'd want to we'd want to switch the products/reactants and multiply the coefficients by . Keep in mind whatever we do to the equation, we do to the ΔH. Should look like:
N₂ + H₂ --> NH₃ (ΔH=-45.9)
C + 2H₂ --> CH₄ (ΔH=-74.9)
HCN --> H₂ + C + N₂ (ΔH=-135)
CH₄ + NH₃ --> HCN + 3H₂
Everything cancels, so that means we can add all the ΔH, which should be -255.8 kj/mol, but we also change the sign in order to reflect what's happening in the reaction. (Sorry this is so long)
B) Any oxygen atom contains 8 electrons and 9 neutrons but these vary in the number of protons - 8 and 10 respectively.
C) The oxygen allotropes contain 8 electrons but each contains a different number of neutrons and protons - 8 and 10 respectively.
D) Both oxygen isotopes contain 8 electrons and 8 protons but each contains a different number of neutrons - 8 and 10 respectively.
Copper has been used in electrical wiring for two hundred years. Identify which molecular level property does not contribute to copper's usefulness a material for wiring. A) high ductility B) high malleability C) high conductivity D) high crystallinity
Describe how light is emitted from an atom.
A) As protons absorb energy they travel from the nucleus through the atom emitting light along the way.
B) The light is emitted when energy from sunlight is absorbed by the atom to excite a neutron into a higher level.
C) When the nucleus absorbs sunlight, photons are energized and move to a higher energy level and are then released.
D) Light is emitted from an atom as an electron falls from an excited state to the ground state releasing a photon.
During chemistry, Dan mixes two clear, colorless solution and mixing them produces a yellow precipitate in a clear, colorless final solution as shown by the chemical equation.
Pb(NO3)2(aq) + 2KI(aq) → PbI2(s) + 2KNO3(aq)
What physical evidence indicates that there has been a chemical reaction?
A) The solution changes color.
B) Precipitate formation occurs.
C) The beaker changes temperature.
D) Gas bubbles form during the reaction.
This is due to the difference in density. The rock is denser than the leaf. And also, the rock is denser than the liquid in the pond. If the material is denser than the other material, it will sink. The same holds true for the rock, it sinks. But when the material is less dense than the other material, it floats. And it holds true for the leaf, it floats.
Answer:
Iridium becomes superconducting at extremely low temperatures, and its critical temperature (Tc) for superconductivity is approximately 0.11 Kelvin (K), or 0.11°C.
Explanation:
Given that the critical temperature is given to two significant digits (0.11), your answer should also have two significant digits. Therefore, the temperature at which iridium becomes superconducting is approximately 0.11°C.