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sertanlavr [38]
3 years ago
5

Name a machine used to reap, thresh and clean the crop.i will give brainliest who answers first

Chemistry
1 answer:
meriva3 years ago
4 0

Answer:

combine harvester, or a combiner.

You might be interested in
Is it posible Count a grain of sand?explain
Alla [95]

Answer:

Yes

Explanation:

As long as its a solid, you can count it. It will be hard, but possible.

5 0
3 years ago
Which of the following provides the most evidence for the theory of plate tectonics?
zhenek [66]

Answer:

i dunno

Explanation:

m xlaklXMLXL

5 0
3 years ago
Calculate the concentration of all species in a 0.160 m solution of h2co3.
enot [183]

             H₂CO₃ ⇔       HCO₃⁻   +     H⁺

I            0.160               0                 0

C            -x                  +x               +x

E          0.160-x          +x                +x

Ka1 = [HCO₃⁻][H⁺] / [H₂CO₃]

4.3 x 10⁻⁷ = x² / (0.160-x)   (x is neglected in 0.160-x = 0.160)

x² = 6.88 x 10⁻⁸

x = 2.62 x 10⁻⁴

             HCO₃⁻    ⇔            CO₃⁻²    +   H⁺

I          2.62 x 10⁻⁴               0                2.62 x 10⁻⁴

C          -x                            +x              +x

E       2.62 x 10⁻⁴ - x           +x              2.62 x 10⁻⁴ + x

Ka2 = [CO₃⁻²][H⁺] / [HCO₃⁻]

5.6 x 10⁻¹¹ = x(2.62 x 10⁻⁴ + x) / (2.62 x 10⁻⁴ - x)

x = 5.6 x 10⁻¹¹

Thus,

[H₂CO₃] = 0.160 - (2.62 x 10⁻⁴) = 0.16 M

[HCO₃⁻] = 2.62 x 10⁻⁴ - ( 5.6 x 10⁻¹¹) = 2.6 x 10⁻⁴ M

[CO₃⁻²] = 5.6 x 10⁻¹¹ M

[H₃O⁺] = 2.62 x 10⁻⁴ + 5.6 x 10⁻¹¹ = 2.6 x 10⁻⁴ M

[OH⁻] = 3.8 x 10⁻¹¹

8 0
3 years ago
Iron has density 7.87 g/cm^3. if 52.4 g of iron is added to 75.0 mL of water in a graduated cylinder, to what volume reading wil
vlada-n [284]

Answer:

6.66 mL

Explanation:

The increase in the volume is due to the addition of the iron whose volume can be calculated as:

Using,

Density = Mass / Volume

Given that:

Density of Iron = 7.87 g/cm³

Mass of iron = 52.4 g

Thus, volume is:

Volume = Mass / Density = 52.4 / 7.87 cm³ = 6.66 cm³

Also, 1 cm³ = 1 mL

<u>The rise in the volume = 6.66 mL</u>

8 0
3 years ago
The oxidation of Cu₂O(s) to CuO(s) is an exothermic process:
Alex73 [517]

Answer:

w = 7376.6 J

Explanation:

To calculate the work done in the system, we need first to calculate the number of moles of all compounds.

The following expression, that comes from the 1° law of thermodynamic, will help you to get the work:

w = ΔnRT

Where:

Δn: difference in the number of moles between products and reactants

R: constant universal of gases (8.314 J / mol K)

T: Temperature in Kelvin.

As we are doing this reaction in STP, then the Pressure is 1 atm, and temperature is 0 °C or 273 K.

Now, we already have the moles of Cu₂O, let's see, according to the balanced reaction, how many moles we should have of O₂ and CuO.

If 1 mole of O₂ reacts with 2 moles of Cu₂O then 6.5 moles of Cu₂O will be:

moles O₂ = 6.5 moles Cu₂O * (1 mole O₂/2 moles Cu₂O) = 3.25 moles O₂

If 2 moles of Cu₂O produces 4 moles of CuO, then 6.5 moles will be:

moles CuO = 6.5 moles Cu₂O*(4 moles CuO/2 moles Cu₂O) = 13 moles CuO

Now that we have the moles, let's calculate the value of Δn.

Δn = moles product - moles reactants

Δn = 13 - (6.5 + 3.25) = 3.25 moles

Now, we can calculate the work done in the system:

w = 3.25 * (8.314 * 273)

<h2>w = 7376.6 J or 7.3766 kJ</h2>

Hope this helps

8 0
3 years ago
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