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kozerog [31]
3 years ago
7

Which of these is an indication that a chemical reaction has occurred?

Chemistry
2 answers:
kirill [66]3 years ago
8 0
C. Formation of a precipitate.
Kobotan [32]3 years ago
7 0

<u><em>Answer:</em></u>

  • The correct option is C.
  • Formation of a precipitate

<u><em>Explanation:</em></u>

During a chemical reaction, new substances are formed known as a products, mostly reaction occur and their product is obtained as precipitates.

<u><em>Example</em></u>

Arylidene-2-thiobarbituric acid is obtained as precipitates when aldehyde and thiobarbituric acid react to each other.

melting of a substance

It is just indication of physical changes, like melting of ice, composition remained same as before.

boiling of a substance

It is just indication of physical changes, like boiling of water into vapors, composition remained same as before.

freezing of a substance

It is just indication of physical changes, like freezing of water into ice, composition remained same as before

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An atom having 52 protons and 54 electrons would have an atomic number of 52 and a net charge of -2. This element would be 52 Te 2-, or choice A.
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What time of the year can you see Scorpius
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Answer:

In the northern hemisphere I believe, Scorpius is most visible by looking to the south during July and August around 10:00 PM. The constellation remains visible until mid-September. In the southern hemisphere, Scorpio appears very high in the northern part of the sky until close to the end of September.

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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
BartSMP [9]

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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3 years ago
Three forms of radiation are also called ionizing radiation
Trava [24]

Answer:

Alpha Particle, Beta Particles and Gamma Rays

Explanation:

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2 <span>KOH +1 H3AsO4 →1 K2HAsO4 + 2 H2O</span>
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