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3 years ago

Define mechanical wave (make sure to use the word “medium”)

Chemistry

1 answer:

Zinaida [17]3 years ago

7 0

Answer:

A mechanical wave is a wave that is an oscillation of matter, and therefore transfers energy through a medium. While waves can move over long distances, the movement of the medium of transmission—the material—is limited. Therefore, the oscillating material does not move far from its initial equilibrium position.

Explanation:

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are medications typically used to relieve excessive mucus in nasal pathways. a) Radioactive isotopes b) Expectorants c) Deconges

Mrac [35]

Answer:

c) decongestants relive excessive muscle in nasal pathways

8 0

3 years ago

A 250 gram sample of water at the boiling point had 45.0 kj of heat added. how many grams of water were vaporized? heat of vapor

Julli [10]

You have 45 kJ of heat added and for every 40.6 kJ added, one mole is able to be vaporized. Find how many moles you can vaporize.

45 kJ / 40.6 kJ = 1.1 moles

Water is roughly 18 g per mole so 1.1 moles x 18 g per mol = 19.95 grams vaporized

Hope I helped!

7 0

4 years ago

During chemistry, Dan mixes two clear, colorless solution and mixing them produces a yellow precipitate in a clear, colorless fi

kondor19780726 [428]

Answer : Formation of yellow precipitate is the physical evidence that there has been a chemical reaction.

Explanation :

A chemical reaction happens when 2 or more substances chemically react with each other.

There are 4 evidences indicating that a chemical reaction has occurred which are mentioned below.

1. Change in color : On mixing, the reaction mixture can change color indicating that a chemical change may have occurred.

2. Formation of precipitate : A reaction in which a solid is formed on mixing 2 aqueous solutions is called as precipitation reaction. Here, the formation of solid indicates a chemical change.

ex. $AgNO_{3} (aq) + NaCl (aq) \rightarrow AgCl (s) + NaNO_{3} (aq)$

In above reaction, on mixing the solutions, a white precipitate of AgCl is formed which indicates a chemical change.

3. Evolution of gas : A chemical change also occurs when a gas is evolved on mixing 2 substances.

ex. $2HCl (aq) + Na_{2}CO_{3} (aq) \rightarrow 2NaCl (aq) + H_{2}O (l) + CO_{2} (g)$

In above reaction, CO2 gas is evolved and bubbles can be seen in the form of effervescence.

4. Change in temperature : Certain chemical reactions absorb or evolve heat. When a chemical reaction evolves heat, the temperature of the final reaction mixture increases and when it absorbs heat, the temperature decreases. This increase and decrease in temperature indicates a chemical change.

ex. $HCl (aq) + NaOH (aq) \rightarrow NaCl(aq) + H_{2}O (l)$

In above reaction, the final mixture becomes hot as the reaction releases heat. ( Exothermic)

Change in odor also indicates a chemical change.

For the given reaction, a yellow precipitate of PbI2 is getting formed.

Therefore formation of this precipitate is the physical evidence that there has been a chemical reaction.

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3 years ago

Which of the following statements is true regarding bacteria and animal cells?

Fantom [35]

The most accurate answer is A.

Bacterial cells are generally very small, almost 10 times smaller than most animal and plant cells. Most bacterial cells measure about 0.2 to 10 microns or micrometers which in inches is 0.0000079 to 0.00039.

One of the reasons that bacterial cells are so small is that they require a large surface area to volume ratio to be able to take in nutrients. They take in nutrients from their surroundings through the process of diffusion.

3 0

4 years ago

When vinegar and baking soda are combined bubbles begin to form. Bubbles are evidence of a chemical reaction because they

Varvara68 [4.7K]

Answer:

bubbled

Explanation:

its simple they bubbled

signs of chemical reactions are change of

odor

bubbles

solid turns liquid

liquid turns solid

change of color

7 0

3 years ago