D)By increasing or decreasing the size of systems that are difficult to study we make it easier for students to see how they work and therefore make it easier for them to learn.
Explanation:
Scientific models makes it easier to teach students about systems because their sizes can be adjusted and this makes it easier for students to see how they work.
A model is a simplification of the real work. It takes a part of the real world and studies it.
Models are highly desired in teaching and understanding very complex systems.
- Since a tutor owns the control of the model, they can make adjustments on them to a scale that is convenient to work with.
- Also, a part of a system can be studied one at a time making it simple for students to comprehend.
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Answer:
1. Ionic bond
2. High melting point and high boiling point for ionic bonds while covalent bonds have low melting and boiling point.
3. The similarity is that ionic and covalent bonding lead to the creation of stable molecules.
4. 4Fe + 3O2 → 2Fe2O3
5. It uses the process of fission.
6. Fission involves the splitting of radioactive elements into smaller particles/compounds while Fusion involves combining of two or more atomic nuclei to form one or more different atomic nuclei and subatomic particles.
7. Nuclear power plants produce little to no greenhouse gas.
Nuclear power plants produce a large amount of energy for a small mass of fuel.
Nuclear is less expensive.
The only metal that is a liquid at room temperature is mercury!!
Answer:
The acid must be a concentrated acid
Explanation:
Ethene is prepared in the laboratory by heating ethanol with excess concentrated tetraoxosulphate VI acid at 170°C . The reactionoccursc in two stages;
1) when the ethanol and sulphuric acid are mixed in a ratio of 1:2, ethyl hydrogentetraoxosulpate VI is formed
2) The compound formed in the first step is heated in the presence of excess concentrated sulphuric acid to give ethene and sulphuric acid.
The overall reaction can be perceived as the dehydration of ethanol. The gas produced (ethene) is usually passed through sodium hydroxide solution to remove any gaseous impurities present.
concentrated sulphuric acid is used in this process since it is a good dehydrating agent.
Answer:
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- <u><em>Concentrated</em></u>
Explanation:
Concentration measures the amount of solute in a solution. There are many expressions of concentration. Some of then are percentage (mass/mass, volume/mass, volume/volume), molarity, molality, mole fraction, among others.
When a solution has a high concentration it is said that it is <em>concentrated; </em>when a solution has a low concentration is is said that is is diluted.
Concentrated solutions expressed in percentage typically have about 80 - 90% (or more) of solute.
Diluted solutions expressed in percentage, tipylcally have about 10% - 20% or less.
But they are not fixed limits. You might say that a 85% solution is concentrated. Acids at 75 % sure are concentrated.
Hence, a 93.3% solution is concentrated, definitely.
