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creativ13 [48]
2 years ago
10

3)

Chemistry
1 answer:
Vikentia [17]2 years ago
6 0

Answer:

A

Explanation:

I think it is A because a dinosaurs are extinct so it wold be possible to find a dinosaur fossil in the coal mine.

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What would happen if you took a normal shaped bottle, sailed it at 1,000 feet, and then carried it up to 14,000 feet
Dovator [93]

it would go 15000 feet

4 0
3 years ago
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How many grams of barium sulfate, BaSO 4 , be precipitated when 2.25 moles of sodium sulfate , Na 2 SO 3 , reacts with an excess
gulaghasi [49]

Answer:

525.1 g of BaSO₄ are produced.

Explanation:

The reaction of precipitation is:

Na₂SO₄ (aq) + BaCl₂ (aq) →  BaSO₄ (s) ↓  +  2NaCl (aq)

Ratio is 1:1. So 1 mol of sodium sulfate can make precipitate 1 mol of barium sulfate.

The excersise determines that the excess is the  BaCl₂.

After the reaction goes complete and, at 100 % yield reaction, 2.25 moles of BaSO₄ are produced.

We convert the moles to mass: 2.25 mol . 233.38 g/mol = 525.1 g

The precipitation's equilibrium is:

SO₄⁻² (aq)  +  Ba²⁺ (aq)  ⇄  BaSO₄ (s) ↓       Kps

7 0
2 years ago
1. what is an ethical concern about biotechnology
Anastasy [175]

Answer:

1. There are so many ethical concerns about biotechnology, some Ethical issues that arise from the application of modern biotechnologies include:

Discrimination of individuals because of their health or health history as a result of knowing their genetic information,  minimizing harms while maximizing benefits, Interference with nature, privacy.

2. a. Plants (maize, rice)

   b. Fish (GloFish)

3. For individuals, biotechnology has helped in the prevention and treatment of a wide range of diseases. For society, biotechnology saves time, improves the health and quality of food through a reduction in the use of pesticides and it can create new viruses and bacteria that cause diseases. Biotechnology could address global change since more genetically modified plants are grown.

8 0
3 years ago
Calculate the standard enthalpy of formation of NOCl(g) at 25 ºC, knowing that the standard enthalpy of formation of NO(g) at th
stepan [7]

Answer:

The standard enthalpy of formation of NOCl(g) at 25 ºC is 105 kJ/mol

Explanation:

The ∆H (heat of reaction) of the combustion reaction is the heat that accompanies the entire reaction. For its calculation you must make the total sum of all the heats of the products and of the reagents affected by their stoichiometric coefficient (number of molecules of each compound that participates in the reaction) and finally subtract them:

Enthalpy of the reaction= ΔH = ∑Hproducts - ∑Hreactants

In this case, you have:  2 NOCl(g) → 2 NO(g) + Cl₂(g)

So, ΔH=2*H_{NO} +H_{Cl_{2} }-2*H_{NOCl}

Knowing:

  • ΔH= 75.5 kJ/mol
  • H_{NO}= 90.25 kJ/mol
  • H_{Cl_{2} }= 0 (For the formation of one mole of a pure element the heat of formation is 0, in this caseyou have as a pure compound  the chlorine Cl₂)
  • H_{NOCl}=?

Replacing:

75.5 kJ/mol=2* 90.25 kJ/mol + 0 - H_{NOCl}

Solving

-H_{NOCl}=75.5 kJ/mol - 2*90.25 kJ/mol

-H_{NOCl}=-105 kJ/mol

H_{NOCl}=105 kJ/mol

<u><em>The standard enthalpy of formation of NOCl(g) at 25 ºC is 105 kJ/mol</em></u>

8 0
3 years ago
Label the following as either a chemical or a physical change.
Delicious77 [7]
Physical,physical, chemical, chemical, physical, chemical
7 0
3 years ago
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