Please answer number 76,77 and 78.

Answer:

Final number of moles = 0.675 mol

Mass = 2.7 g

Explanation:

Given data:

Initial volume of gas = 2.00 L

Final volume of gas = 2.70 L

Initial number of moles = 0.500 mol

Final number of moles = ?

Solution:

Formula:

V₁/n₁ = V₂/n₂

V₁ = Initial volume

n₁ = Initial number of moles

V₂ = Final volume of gas

n₂ = Final number of moles

Now we will put the values in formula.

2.00 L /0.500 mol = 2.70 L / n₂

n₂ = 2.70 L× 0.500 mol /2.00 L

n₂ = 1.35 L.mol / 2.00 L

n₂ = 0.675 mol

B)

Grams of helium added = ?

Solution:

Mass = number of moles × molar mass

Mass = 0.675 mol× 4 g/mol

Mass = 2.7 g

548.55 grams of aluminum hydroxide should theoretically form.

Explanation:

Balanced equation for the reaction:

3 NaOH + Al ⇒ Al(OH)3 +3 Na

DATA GIVEN:

mass of NaOH = 842 grams, atomic mass =39.9 grams/mole

mass of Al = 750 grams, atomic mass = 26.9 grams/mole

aluminum hydroxide theoretical yield = ?

Moles of NaOH reacted

number of moles =

putting the values in the equation

NaOH =

           = 21.1 MOLES OF NaOH

Al =

   = 27.8 moles

from the equation

 from 3 moles of NaOH 1 mole of Al(OH)3 is produced

21.1 moles of NaOH will react to give x moles of Al(OH)3

=

7.03 moles of Al(OH)3 is formed.

and

1 mole of Al(OH)3 is formed from 1 mole of Al in the reaction

so, 27.8 Moles will react to give give 27.8 moles of Al(OH)3 limiting reagent of the given reaction is NaOH

mass of Al(OH)3 =7.03 x 78 (atomic mass of Al(OH)3)

          = 548.55 grams

theoretical  yield from the given data is 548.55 grams

Answer:

They make food by using chemosynthesis.

Explanation:

Final answer:

Deep-water bacteria, known as chemoautotrophs, make their own food through a process called chemosynthesis, using chemicals like hydrogen sulfide from hydrothermal vents instead of sunlight.

Explanation:

Some deep-water bacteria in the ocean are known as chemoautotrophs, which can produce their own food by using chemical energy from hydrothermal vents. Unlike plants, they do not use sunlight for photosynthesis. Instead, they rely on chemosynthesis for their energy supply. In this process, bacteria convert chemicals from the vents into usable energy or food. For example, some bacteria use hydrogen sulfide, a chemical abundant in the deep ocean, for chemosynthesis. This biological process allows these deep-water bacteria to thrive in environments where sunlight is not available.

Learn more about Chemosynthesis here:

brainly.com/question/17014236

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