D. is the missing element.
Carlos <em>hasn’t done research</em> on what other scientists have observed and investigated on this topic. If he hasn’t done his literature research, he may just be repeating the experiments of other scientists working in the same area.
Options “A.”, “B.”, and “C.” are all part of the scientific method.
Answer:
Manganese dioxide is a catalyst.
Explanation:
The decomposition of hydrogen peroxide into water and oxygen is a slow reaction and MnO₂ is used as a catalyst to speed up the reaction.
The role of MnO₂ (catalyst):
- Chemical reactions occur faster in the presence of a catalyst because the catalyst provides an alternative reaction pathway with a lower activation energy than the non-catalyzed mechanism.
- In catalyzed mechanisms, the catalyst usually reacts to form a temporary intermediate, which then regenerates the original catalyst in a cyclic process.
- A substance which provides a mechanism with a higher activation energy does not decrease the rate because the reaction can still occur by the non-catalyzed route.
- The catalyst does not used up in the reaction.
So, the right choice is:
Manganese dioxide is a catalyst.
Answer:
Explanation:
HCl + NaOH ⟶ NaCl + H₂O
There are two energy flows in this reaction.
Heat of reaction + heat to warm water = 0
q₁ + q₂ = 0
q₁ + mCΔT = 0
Data:
m(HCl) = 50 g
m(NaOH) = 50 g
T₁ = 22 °C
T₂ = 28.87 °C
C = 4.18 J·°C⁻¹g⁻¹
Calculations:
m = 50 + 50 = 100 g
ΔT = 28.87 – 22 = 6.9 °C
q₂ = 100 × 4.18 × 6.9 = 2900 J
q₁ + 2900 = 0
q₁ = -2900 J
The negative sign tells us that the reaction produced heat.
The reaction produced .
One of the hydrogens in the NH3 is replaced in the first reaction by the methyl group, or -CH3. The NH3 can have more than one H substituted for it, therefore the final product frequently comprises a blend of methylamine, dimethylamine, and trimethylamine.
A halogenoalkane and ethanolic ammonia can be used in a nucleophilic substitution process to produce primary aliphatic amines like methylamine (CH3NH2).
NH3 + CH3Cl = HCl + CH3NH2
The process is challenging because any unreacted ammonia can react with the generated HCl:
NH3+HCl yields NH4Cl.
Since the N in CH3NH2 still has a single pair of electrons, it can act as a base and interact with the HCl that is created in one of the following ways:
CH3NH2+HCl becomes CH3NH3+Cl.
or as a nucleophile and react with any chloromethane that hasn't been reacted:
(CH3)2NH + HCl = CH3NH2 + CH3Cl
Learn more about nucleophilic substitution here-
brainly.com/question/28325919
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46.3
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