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2 years ago

Choose all the answers that apply.

Chemistry

2 answers:

SVETLANKA909090 [29]2 years ago

8 0

Answer:

A. burning of fossil fuels

B. respiration

Explanation:

Fossil fuels such as petrol, diesel and coal are used in the movement of cars. These fuels are burnt inside the engine of vehicles and carbondioxide is released. Respiration is energy releasing process in which energy is released in the form of Adenine tri phosphate. In respiration, carbondioxide is released when glucose is broken down inside the mitochondria of the cell with the addition of oxygen.

LenKa [72]2 years ago

3 0

Burning of fossil fuels: when we burn fossil fuels, CO2 is produced

Respiration: when animals respire, they convert O2 to CO2 which is then released into the atmopshere

Hope it helps :)

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A sample of hydrated copper (II) sulfate (CuSO4•nH2O) is heated to 150°C and produces 103.74 g anhydrous copper (II) sulfate and

wariber [46]

Answer:

Explanation:

Firstly, we convert what we have to percentage compositions.

There are two parts in the molecule, the sulphate part and the water part.

The percentage compositions is as follows:

Sulphate- (103.74)/(103.74 + 58.55) × 100% = apprx 64%

The water part = 100 - 64 = 36%

Now, we divide the percentages by the molar masses.

For the CuSO4 molar mass is 64 + 32 + 4(16) = 160g/mol

For the H2O = 2(1) + 16 = 18g/mol

Now we divide the percentages by these masses

Sulphate = 64/160 = 0.4

Water = 36/18 = 2

The ratio is thus 0.4:2 = 1:5

Hence, there are 5 water molecules.

3 0

3 years ago

Nault 25000L 250 our = 25000L 15040 8. How many grams of CaCl2 are needed to make 150.0 mL of a 0.500 M CF solution? (Note: CaCl

yuradex [85]

Answer:

You need 8,324 g of CaCl₂ yo make this solution

Explanation:

Molarity is a way to express concentration in a solution, in units of moles of solute per liter of solution.

To know the grams of CaCl₂ it is necessary to know, first, the moles of this substance with the desired volume and concentration , thus:

0,1500 L × $\frac{0,500 mol}{L}$ = 0,075 CaCl₂ moles

Now, with the molar mass of CaCl₂ you will obtain the necessary grams, thus:

0,075 CaCl₂ moles × $\frac{110,98 g}{mol}$ = 8,324 g of CaCl₂

So, you need 8,324 g of CaCl₂ to make 150,0 mL of a 0,500M solution

I hope it helps!

3 0

3 years ago

Can some atoms exceed the limits of the octet rule in bonding? If so, give an example.

harkovskaia [24]

Answer:

Yes. Example: Sulfur hexafluoride (SF₆) molecule

Explanation:

According to the octet rule, elements tend to form chemical bonds in order to have 8 electrons in their valence shell and gain the stable s²p⁶ electronic configuration.

However, this rule is generally followed by main group elements only.

Exception: SF₆ molecule

In this molecule, six fluorine atoms are attached to the central sulfur atom by single covalent bonds.

Each fluorine atom has 8 electrons in their valence shells. Thus, it follows the octet rule.

Whereas, there are 12 electrons around the central sulfur atom in the SF₆ molecule. Therefore, sulfur does not follow the octet rule.

Therefore, the SF₆ molecule is known as a hypervalent molecule or expanded-valence molecule.

6 0

3 years ago

A salt is best described as a compound that is formed from the reaction between

kaheart [24]

Answer:

Explanation:

5 0

3 years ago

1. A gas expands and does p-v work on the surroundings equal to

azamat

The change in energy of the system : -63 J

<h3>Further explanation</h3>

Given

279 J work

216 J heat

Required

The change in energy

Solution

Laws of thermodynamics 1

ΔU=Q+W

Rules :

receives heat, Q +
releases heat, Q -
work is done by a system, W -
work is done on a system, W +

a gas work on the surrounding : W =-279 J

a gas absorb heat from surrounding : Q = +216 J

Internal energy :

= -279+216

= -63 J

3 0

2 years ago