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ira [324]
3 years ago
8

Three-quarters of the elements are..

Chemistry
1 answer:
Dennis_Churaev [7]3 years ago
8 0

Answer:

metals

Explanation:

Approximately three-quarters of all known chemical elements are metals. The most abundant varieties in the Earth's crust are aluminum,... Gold (Au), chemical element, a dense lustrous yellow precious metal of Group 11 (Ib), Period 6, of the periodic table.

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What are the 4 variables that describe a gas
Phantasy [73]
Pressure, volume, temperature, # moles Pressure, volume and temperature, and moles of gas


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8 0
3 years ago
What is the theoretical yield of vanadium, in moles, that can be produced by the reaction of 1.0 mole of V2O5 with 4.0 mole of c
yuradex [85]

Answer:

Theoretical moles of V are 1.6 moles

Explanation:

The theoretical yield of a reaction is defined as the amount of product you would make if all of the limiting reactant was converted into product.

In the reaction:

V2O5(s) + 5Ca(i) → 2V(i) + 5CaO(s)

Based on the reaction, 1 mol of V2O5 needs 5 moles of Ca for a complete reaction. As there are just 4 moles, <em>limiting reactant is Ca.</em> As there are produced 2 moles of V per 5mol of Ca, Theoretical moles of V are:

4 moles of Ca × (2mol V / 5Ca) = <em>1.6 moles of V</em>

<em></em>

I hope it helps!

5 0
2 years ago
When performing physical exercise, the heart rate, by what percentage can it be increased?
Dafna11 [192]

Answer:

10

Explanation:

I did that already. You got beo

4 0
3 years ago
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Precipitation calculations with Ni2+ and Pb2+
Maurinko [17]

Precipitation calculations with Ni²⁺ and Pb²⁺ a. Use the solubility product for Ni(OH)₂ (s) . the pH at which Ni(OH)₂ begins to precipitate from a 0.18 M Ni²⁺ solution. (Ksp Ni(OH)₂ = 5.5x10⁻¹⁶) is 6.8.

When Ni(OH)₂ starts precipitate :

Ksp of Ni(OH)₂ = [ Ni²⁺ ] [ OH²⁻ ]

5.5x10⁻¹⁶ = [ 0.18 ] [ OH²⁻ ]

[ OH²⁻ ] = 5.5x10⁻¹⁶ / 0.18

[ OH⁻ ] = 5.5 × 10⁻⁸ M

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therefore , pH = 14 - 7.2

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Thus, Precipitation calculations with Ni²⁺ and Pb²⁺ a. Use the solubility product for Ni(OH)₂ (s) . the pH at which Ni(OH)₂ begins to precipitate from a 0.18 M Ni²⁺ solution. (Ksp Ni(OH)₂ = 5.5x10⁻¹⁶) is 6.8.

To learn more about pH here

brainly.com/question/15289741

#SPJ1

6 0
11 months ago
Which component is required for the activation of some enzymes?
shepuryov [24]
The best answer is letter A. 
The main factors that change the speed of enzymatic reactions are temperature, pH and substrate concentration (quantity). <span>There are enzymes that need other associated molecules to work. These molecules are called enzyme co-factors. They can be organic ions like mineral salts.</span>
5 0
3 years ago
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