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gladu [14]
3 years ago
13

Student mixes 5 g of sand into a beaker of 20 g of water. Is this a physical or chemical change-why?

Chemistry
1 answer:
jek_recluse [69]3 years ago
6 0
Physical because it doesn't do with fire
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Phosphorous pentoxide, P2O5(s), is produced from the reaction between pure oxygen and pure phosphorous (P, solid). What is the v
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Answer:

4190.22 L = 4.19 m³.

Explanation:

  • For the balanced reaction:

<em>2P₂ + 5O₂ ⇄ 2P₂O₅. </em>

It is clear that 2 mol of P₂ react with <em>5 mol of O₂ </em>to produce <em>2 mol of P₂O₅.</em>

  • Firstly, we need to calculate the no. of moles of 6.92 kilograms of P₂O₅ produced through the reaction:

no. of moles of P₂O₅ = mass/molar mass = (6920 g)/(283.88 g/mol) = 24.38 mol.

  • Now, we can find the no. of moles of O₂ is needed to produce the proposed amount of P₂O₅:

<u><em>Using cross multiplication:</em></u>

5 mol of O₂ is needed to produce → 2 mol of P₂O₅, from stichiometry.

??? mol of O₂ is needed to produce → 24.38 mol of P₂O₅.

∴ The no. of moles of O₂ needed = (5 mol)(24.38 mol)/(2 mol) = 60.95 mol.

  • Finally, we can get the volume of oxygen using the general law of ideal gas:<em> PV = nRT.</em>

where, P is the pressure of the gas in atm (P = 606.1 mm Hg/760 = 0.8 atm).

V is the volume of the gas in L (V = ??? L).

n is the no. of moles of the gas in mol (n = 60.95 mol).

R is the general gas constant (R = 0.0821 L.atm/mol.K),

T is the temperature of the gas in K (396.90°C + 273 = 669.9 K).

∴ V of oxygen needed = nRT/P = (60.95 mol)(0.0821 L.atm/mol.K)(669.9 K)/(0.8 atm) = 4190.22 L/1000 = 4.19 m³.

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Homeostasis is the balance between your internal and external environments. We
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They are already matched for you. It goes

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in the order of the questions.

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In real-life situations, workers collect water samples in a lake or stream instead of using Samples A and B. For this lab to wor
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The given above pretty much states already that with the presence of the calcium carbonate which acts as the buffer will allow the solution to withstand changes in acidity. The greater the amount, the higher chances that it will be able to withstand the said changes. Therefore, if Lake X had greater ppm of CaCO3 then, it will be able to withstand greater amount of acid rain. 
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What has a density of q
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  • Water has the density of 1.0g/ml
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Which of the following statements about gamma rays are TRUE? I. Gamma rays have low energy II. Gamma rays are a form of light. I
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the third one

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