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nadya68 [22]
3 years ago
9

Alan wants to identify an unknown solid compound. Which statement correctly describes a method he could use to identify the comp

ound?
A: he could find the temperature at which the compound melts because pure substances have definite melting points

B: he could find the mass of the sample because pure substances have definite masses

C: he could use a mesh screen to filter out the different elements that make up the compound

D: he could melt the compound because melting allows the elements of a compound to seperate
Chemistry
1 answer:
vfiekz [6]3 years ago
8 0

A: he could find the temperature at which the compound melts because pure substances have definite melting points

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What is the maximum mass of b4c that can be formed from 2.00 moles of boron(iii) oxide?
anzhelika [568]

The maximum mass of B₄C that can be formed from 2.00 moles of boron (III) oxide is 55.25 grams.

<h3>What is the stoichiometry?</h3>

Stoichiometry of the reaction gives idea about the relative amount of moles of reactants and products present in the given chemical reaction.

Given chemical reaction is:

2B₂O₃ + 7C → B₄C + 6CO

From the stoichiometry of the reaction, it is clear that:

2 moles of B₂O₃ = produces 1 mole of B₄C

Now mass of B₄C will be calculated by using the below equation:

W = (n)(M), where

  • n = moles = 1 mole
  • M = molar mass = 55.25 g/mole

W = (1)(55.25) = 55.25 g

Hence required mass of B₄C is 55.25 grams.

To know more about stoichiometry, visit the below link:

brainly.com/question/25829169

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3 0
2 years ago
At a certain temperature the vapor pressure of pure chloroform (CHCl3) is measured to be 91. torr. Suppose a solution is prepare
OleMash [197]

Answer:

P_{CCl_4}=52.43torr

Explanation:

Hello there!

In this case, sine the solution of this problem require the application of the Raoult's law, assuming heptane is a nonvolatile solute, so we can write:

P_{CCl_4}=x_{CCl_4}P_{CCl_4}^{vap}

Thus, we first calculate the mole fraction of chloroform, by using the given masses and molar masses as shown below:

x_{CCl_4}=\frac{140/153.81}{140/153.81+67.1/100.21}=0.576

Therefore, the partial pressure of chloroform turns out to be:

P_{CCl_4}=0.576*91torr\\\\P_{CCl_4}=52.43torr

Regards!

3 0
3 years ago
Write the ground-state electron configuration for the chloride ion.You may write either the full or condensed electron configura
dalvyx [7]

Answer:

1s^22s^22p^63s^23p^6

Explanation:

Chlorine is the element of group 17 and third period. The atomic number of chlorine is 17 and the symbol of the element is Cl.

The electronic configuration of the element chlorine is:-

1s^22s^22p^63s^23p^5

Chloride ion is formed when chlorine atom gain one more electron. So, the ground-state electron configuration for the chloride ion is:-

1s^22s^22p^63s^23p^6

8 0
3 years ago
What is the chemical reaction that occurs during photosynthesis ​
vfiekz [6]

Answer:

endothermic change occurs

Explanation:

photosynthesis, is an endothermic reaction in which energy is absorbed from the surrounding.

hope this helps

8 0
3 years ago
Read 2 more answers
The enthalpy of vaporization of Bromine is 15.4 kJ/mol. What is the energy change when 80.2 g of Br2 condenses to a liquid at 59
Aleksandr-060686 [28]

The enthalpy of vaporization of Bromine is 15.4 kJ/mol. -7.7 kJ is the energy change when 80.2 g of Br₂ condenses to a liquid at 59.5°C.

<h3>What is Enthalpy of Vaporization ?</h3>

The amount of enthalpy or energy that must be added to a liquid substance into gas substance is called Enthalpy of Vaporization. It is also known as Latent heat of vaporization.

<h3>How to find the energy change from enthalpy of vaporization ?</h3>

To calculate the energy use this expression:

Q = n \Delta H_{\text{vapo.}

where,

Q = Energy change

n = number of moles

\Delta H_{\text{Vapo.}} = Molar enthalpy of vaporization

Now find the number of moles

Number of moles (n) = \frac{\text{Given Mass}}{\text{Molar mass}}

                                   = \frac{80.2\ g }{159.8\ g/mol}

                                   = 0.5 mol

Now put the values in above formula we get

Q = - n \Delta H_{\text{vapo.}         [Negative sign is used because Br₂ condensed here]

   = - (0.5 mol × 15.4 kJ/mol)

   = - 7.7 kJ

Thus from the above conclusion we can say that The enthalpy of vaporization of Bromine is 15.4 kJ/mol. -7.7 kJ is the energy change when 80.2 g of Br₂ condenses to a liquid at 59.5°C.

Learn more about the Enthalpy of Vaporization here: brainly.com/question/13776849

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8 0
1 year ago
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