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3 years ago

Which of the following numbers will produce the same number when rounded to two significant figures? (2.3)

1 answer:

8 0

2.10

The 0 after 1 is not significant and does not affect the value of the number; therefore, when the number will be rounded to two significant figures, it will become 2.1, so it will be the same.

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What is the maximum number of electrons that each of the first three electron orbits can hold, starting from the nucleus?

egoroff_w [7]

First shell from the nucleus can have a maximum of 2 electrons ! hope this helped

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3 years ago

One method of favoring the formation of an ester is to add excess acetic acid.

AleksandrR [38]

Answer: True

Explanation:

An ester refers to the class of organic compounds which react with water in order to produce organic acids, inorganic acids or alcohol. They are usually gotten from carboxylic acids.

A method of favoring the formation of an ester is to add excess acetic acid. Therefore, the above statement is true.

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3 years ago

How could a change to the size of the algae population cause an increase in the size of the moon jelly population? (Be sure to d

timofeeve [1]

Answer:

The deaths of one species leaves room for another to grow. for example is there are not enough wolves to kill the deer the deer population will increase and that would start to cause problems. If there is not enough algae to combat the moon jelly the amount of moon jelly will increase because there is nothing to stop it.

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3 years ago

A large clump of ice is placed into a saucepan and heated to at least 1000C. Explain the changes that would take place by using

Mamont248 [21]

By start heating the water so,
1- the physical changes to the water will begin by going through different states of matter such as solid, liquid and gas vapor.

2- Water is a compound, not an element (H2o).

3- It will change according to the temperature change also:

a- At zero C° it is at a freezing temperature.

b- when it starts to be heated from 0C° to 100 c°, it starts to change from freezing to the liquid state.

c- At 100C° the water starts to change from liquid to vapor state until it disappears.

7 0

3 years ago

Read 2 more answers

You placed a sample of a hydrate of calcium chloride (CaCl2) in a weighed test tube, and weighed the filled test tube.

ziro4ka [17]

Answer:

1. 5g

2. 2.3g

3. 2.7g

4. 0.02mol

5. 0.13mol

6. 7moles

Explanation:

From the question, the following were obtained:

Mass of empty tube = 13.5g

Mass of empty tube + hydrated salt = 18.5g

Mass of tube + anhydrous salt = 16.2g

1. Mass of empty tube = 13.5g

Mass of empty tube + hydrated salt = 18.5g

Mass of hydrated salt = 18.5 — Mass of empty tube

Mass of hydrated salt = 18.5 — 13.5 = 5g

2. Let us calculate the mass of the anhydrous salt.

Mass of tube + anhydrous salt = 16.2g

Mass of empty tube = 13.5g

Mass of anhydrous salt = 16.2 — Mass of empty tube = 16.2 — 13.5

Mass of anhydrous salt = 2.7g

Now we can calculate the mass of the water evolved as follows:

Mass of water = Mass of hydrated salt — Mass of anhydrous

Mass of water = 5 — 2.7 = 2.3g

3. Mass of empty tube = 13.5g

Mass of anhydrous salt = 16.2 — Mass of empty tube = 16.2 — 13.5

Mass of anhydrous salt = 2.7g

4. MM of CaCl2 = 40 +(2x35.5) = 40 + 71 = 111g

Mass of CaCl2 = 2.7g

Number of mole = Mass /Molar Mass

Number of mole of CaCl2 = 2.7/111 = 0.02mol

5. MM of H2O = (2x1) +16 = 2 + 16 = 18g/mol

Mass of H2O = 2.3g

Number of mole = Mass /Molar Mass

Number of mole of H20 = 2.3/18 = 0.13mol

6. To get the mole of water in the molecular formula, we will find the ratio of the number of mole of anhydrous salt to water as shown below:

Mole anhydrous : mole of water ie

0.02 : 0.13 = 1 : 7

Therefore, the mole of water in the formula is 7 ie

CaCl2.7H20

3 0

3 years ago