Answer:
increase in the air pressure
Explanation:
The barometer is a device that is used for measuring the air pressure. It is a device that uses mercury in order to show the air pressure. The mercury reacts easily to the changes in the air pressure, so it is a nice indicator for it. The air pressure can simply be defined as the weight of the air masses, and the pressure they make it because of it on the objects. The lower the air pressure, the higher up the mercury will go, as it will experience less pressure from the air, and the higher the air pressure, the lower the mercury will drop, as it will experience more pressure from the air.
Question is incomplete, the complete question is as follows:
A student wants to examine a substance by altering the bonds within its molecules. Which of the following properties of the substance should the student examine?
A. Toxicity, because it can be observed by altering the state of the substance
B. Boiling point, because it can be observed by altering the state of the substance
C. Toxicity, because it can be observed by replacing the atoms of the substance with new atoms
D. Boiling point, because it can be observed by replacing the atoms of the substance with new atoms
Answer:
B.
Explanation:
A student can examine a substance without altering the bonds within the molecules by examining its boiling point.
The boiling point is the property of a substance, at which the substance changes its state, which is from solid to liquid, liquid to gas and others. So, examining the boiling point will alter the bonds within the molecules as the state of substance will change.
Hence, the correct answer is "B".
Answer:
Reaction 5: Decomposition reaction.
Reaction 6: Single replacement reaction
Reaction 7: Combination reaction.
Reaction 8: Combustion reaction.
Explanation:
<u><em>Reaction 5:</em></u> 2KClO₃ → 2KCl + 3O₂.
- It is a decomposition reaction.
- A decomposition reaction is a type of chemical reaction in which a single compound breaks down into two or more elements or new compounds.
- In this reaction: potassium chlorate decomposes into two single components (potassium chloride and oxygen).
- So, it is a decomposition reaction.
<u><em>Reaction 6:</em></u> Zn + 2HCl → H₂ + ZnCl₂.
- It is a single replacement reaction.
- A single-replacement reaction, a single-displacement reaction, is a reaction by which one (or more) element(s) replaces an/other element(s) in a compound.
- It is most often occur if element is more reactive than the other, thus giving a more stable product.
- In this reaction, zinc metal (more active) displaces the hydrogen to form hydrogen gas and zinc chloride, a salt. Zinc reacts quickly with the acid to form bubbles of hydrogen.
<u><em>Reaction 7:</em></u> N₂O₅ + H₂O → 2HNO₃.
- It is a combination "synthesis" reaction.
- A synthesis reaction has two or more reactants and only one product.
- In this reaction, dinitrogen pentoxide reacts with water to produce nitric acid.
- So, it is considered as a synthetic "combination" reaction.
<u><em>Reaction 8:</em></u> 2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O.
- It is a combustion reaction.
- A combustion reaction is a reaction where hydrocarbon alkane is completely burned in oxygen to produce water and carbon dioxide.
- In this reaction 1.0 mole of ethane is burned to give 4.0 moles of carbon dioxide and 6.0 moles of water.
- So, it is considered as a combustion reaction.
Answer:
When white glue is in the bottle, there's not enough air inside the bottle to cause the water to evaporate to make the glue sticky. Basically, the bottle holds the glue from the air and keeps the glue from going everywhere.
