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Nat2105 [25]
3 years ago
9

What do homologous structures, vestigial structures , and fossils provide evidence of?

Chemistry
1 answer:
antoniya [11.8K]3 years ago
6 0
This question is confusing to me.
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The powder mixture (Cu, Al and Fe) = 10g was oxidized from sufficient chloride acid. 1) What are the possible reactions to the p
Mandarinka [93]

Answer:

1) 2Al + 6HCl ⟶ 2AlCl₃ + 3H₂

    Fe + 2HCl ⟶ FeCl₂ + H₂

2) Cu = 2.5 g; Al = 3.5 g; Fe = 4.0 g  

Explanation:

1) Possible reactions

2Al + 6HCl ⟶ 2AlCl₃ + 3H₂

Fe + 2HCl ⟶ FeCl₂ + H₂

2) Mass of each metal

a) Mass of Cu

The waste was the unreacted copper.

Mass of Cu = 2.5 g

b) Masses of Al and Fe

We have two relations :

Mass of Al + mass of Fe = 10 g - 2.5 g = 7.5 g

H₂ from Al + H₂ from Fe = 6.38 L at NTP

i) Calculate the moles of H₂

NTP is 20 °C and 1 atm.

\begin{array}{rcl}pV & = & n RT\\\text{1 atm} \times \text{6.38 L} & = & n \times 0.08206 \text{ L}\cdot\text{atm}\cdot\text{K}^{-1}\text{mol}^{-1} \times \text{293.15 K}\\6.38 & = & 24.06n \text{ mol}^{-1} \\n & = & \dfrac{6.38}{24.06 \text{ mol}^{-1} }\\\\ & = & \text{0.2652 mol}\\\end{array}

(ii) Solve the relationship

 Let x = mass of Al. Then

7.5 - x = mass of Fe

Moles of Al = x/27

Moles of Fe = (7.5 - x)/56

Moles of H₂ from Al = (3/2) × Moles of Al = (3/2) × (x/27) = x /18

Moles of H₂ from Fe = (1/1) × Moles of Fe = (7.5 - x)/56

∴ x/18 + (7.5 - x)/56 = 0.2652

    56x + 18(7.5 - x) = 267.3

      56x + 135 - 18x = 267.3

                        38x = 132.3

                            x = 3.5 g

Mass of Al = 3.5 g

Mass of Fe = 7.5 g - 3.5 g = 4.0 g

The masses of the metals are Cu = 2.5 g; Al = 3.5 g; Fe = 4.0 g

4 0
3 years ago
Please help me with this question it’s really confusing lol. Question 21. Thank youuuu!! :))
bagirrra123 [75]

Answer:

You must write an article if you think there is a link between it asteroid impact and a dinosaur's extinction. explain the correlation between the two events I'm provide evidence within the article that you write that supports your claims.

8 0
2 years ago
Which is the anode and which is the cathode?
rewona [7]

Answer:

2l- ---> l2 + 2e- is the anode

2H+ + 2e- ---> H2(g) is the cathode

Explanation:

Oxidation occurs when a metal loses two or more electrons in a redox chemical reaction and reduction is when it gains. Thus, oxidation is the anode and reduction is the cathode.

5 0
3 years ago
Plant roots do help to anchor sand dunes in one place?
Snezhnost [94]
No. The answer is false.
Just read that sentence aloud and you'll know that it does not sound right
3 0
3 years ago
3. How much heat is required to raise the temperature of 179g of acetic acid, CH3COOH, from 250C
IgorLugansk [536]

Answer:

Q = 1252.82kJ

Explanation:

Mass = 179g

Initial temperature (T1) = 25°C = (25+273.15)K = 298.15K

Final temperature (T2) = 82.70°C = (82.70 + 273.15)K = 335.85K

Specific heat capacity (c) = 121.3J/g.K

Heat energy (Q) = mc∇T

M = mass of the substance

Q = heat energy

c = specific heat capacity of the substance

∇T = change in temperature of the substance = T2 - T1

Q = mc∇T

Q = 179 × 121.3 × (355.85 - 298.15)

Q = 21712.7 × 57.7

Q = 1,252,822.79

Q = 1252.82kJ

The heat energy required to heat 179g of acetic acid from 25°C to 82.70°C is 1252.82kJ

3 0
2 years ago
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