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3 years ago

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Chemistry

1 answer:

snow_lady [41]3 years ago

4 0

Answer:

This describes primary succession.

Explanation:

In the case of primary succession, the sequence of communities is formed in lifeless habitat. With the formation of the new ecosystem, life evolves gradually. In retreating glacier’s case, the new land is being revealed on its receding.

During the initial stage, the land is void of soil and vegetation. This leads to micro-organisms to breakdown the bedrock and soil formation starts. With the efficient amount of soil creation the new vegetation starts.

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What is the mass of 2.25 x 10^25 atoms of lead

NemiM [27]

Answer: the amount of a substance that contains 6.02 x 1023 respective particles of that

substance

Avogadro’s number: 6.02 x 1023

Molar Mass: the mass of one mole of an element

CONVERSION FACTORS:

1 mole = 6.02 x 1023 atoms 1 mole = atomic mass (g)

Try:

1. How many atoms are in 6.5 moles of zinc?

6.5 moles 6.02 x 1023 atoms = 3.9 x 1024 atoms

1 mole

2. How many moles of argon are in a sample containing 2.4 x 1024 atoms of argon?

2.4 x 1024 atoms of argon 1 mole = 4.0 mol

6.02 x 1023 atoms

3. How many moles are in 2.5g of lithium?

2.5 grams Li 1 mole = 0.36 mol

6.9 g

4. Find the mass of 4.8moles of iron.

4.8 moles 55.8 g = 267.84 g = 270g

1 mole

MOLE PARTICLES

(ATOM)

MASS

(g)

1 mole = molar

mass

(look it up on

the PT!)

1 mole =

6.02 x 1023

atoms

1 mole = 6.02 x 1023 atoms 1 mole = atomic mass (g)

Two Step Problems:

1. What is the mass of 2.25 x 1025 atoms of lead?

2.25 x 1025 atoms of lead 1 mole 207.2g = 7744.19g = 7740g

6.02 x 1023 atoms 1 mole

2. How many atoms are in 10.0g of gold?

10 g gold 1 mole 6.02 x 1023 atoms = 3.06 x 1022 atoms

197.0g 1 mole

PRACTICE PROBLEMS:

1. How many moles are equal to 625g of copper?

625g of copper 1 mol = 9.77 mol Cu

64 g Cu

2. How many moles of barium are in a sample containing 4.25 x 1026 atoms of barium?

4.25 x 1026 atoms of barium 1 mol = 706 mol

6.02 x 1023 atoms

3. Convert 2.35 moles of carbon to atoms.

2.35 moles 6.02 x 1023 atoms = 1.41 x 1024 atoms

1 mole

4. How many atoms are in 4.0g of potassium?

4.0 g 1 mole 6.02 x 1023 atoms = 6.2 x 1022 atoms

39.1 g 1 mole

1 mole = 6.02 x 1023 atoms 1 mole = atomic mass (g)

5. Convert 9500g of iron to number of atoms in the sample.

9500 g Fe 1 mole 6.02 x 1023 atoms = 1.0 x 1026 atoms

55.8g 1 mole

6. What is the mass of 0.250 moles of aluminum?

0.250 moles 27.0g = 6.75 g Al

1 mole

7. How many grams is equal to 3.48 x 1022 atoms of tin?

3.48 x 1022 atoms 1 mole 118.7g = 6.86 g Sn

6.02 x 1023 atoms 1 mole

8. What is the mass of 4.48 x 1021 atoms of magnesium?

4.48 x 1021 atoms 1 mole 24.3g = 0.181 g Mg or 1.8 x 10-1

6.02 x 1023 atoms 1 mole

9. How many moles is 2.50kg of lead?

2.50kg 1000 g 1 mol = 12.1 mol

1 kg 207.2 g

10.Find the mass, in cg, of 3.25 x 1021 atoms of lithium.

3.25 x 1021 atoms 1 mol 6.9g 100cg = 3.7

Explanation:

5 0

3 years ago

Un estudiante debe preparar una disolución 2M de NaCl (58,44 g/mol) en un recipiente de 7L. ?Cuántos gramos de NaCl debe agregar

Gnesinka [82]

Answer:

818.2 g.

Explanation:

Molarity is the no. of moles of solute per 1.0 L of the solution.

M = (no. of moles of NaCl)/(Volume of the solution (L))

M = 2.0 M.

no. of moles of NaCl = ??? mol,

Volume of the solution = 7.0 L.

∴ (2.0 M) = (no. of moles of NaCl)/(7.0 L)

∴ (no. of moles of NaCl) = (2.0 M)*(7.0 L) = 14.0 mol.

To find the mass of NaCl, we can use the relation:

no. of moles of NaCl = mass/molar mass

∴ mass of NaCl = (no. of moles of NaCl)*(molar mass) = (14.0 mol)*(58.44 g/mol) = 818.2 g.

3 0

3 years ago

When concentrated sulfuric acid is poured onto sugar in a beaker and stirred, a vigorous exothermic reaction eventually occurs.

Vlada [557]

Missing question:
I. switching from granulated sugar to pow-dered sugar.
II. switching from powdered sugar to gran-ulated sugar.
III. warming up the sulfuric acid.
IV. putting the sulfuric acid container in an ice bath before use.
1. IV only
2. II only
3. III only
4. I and IV
5. I and III.
6. I only.
7. II and III
8. II and IV.
Answer is: 5. I and III.
If the surface area and temperature are increased, speed of reaction also increased.

7 0

3 years ago

How many molecules are there in 122 grams of NO2

AnnyKZ [126]

Thus, there are 1.47 × 10^(23) molecules present in 122 grams of NO2.

3 0

2 years ago

which of the following features provides evidence of a glacier and establishes its directed of movement?

mariarad [96]

Answer:

The pressure from the weight of the glacier generates a layer of water that helps the ice glacier move downslope. This process is called basal sliding. Also, the glacier begins to move under its own weight. The glacier is so heavy and exerts so much pressure that the firn and snow melt without any increase in temperature.

5 0

2 years ago