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When a substance is entering a phase change, the gain or loss of heat is a result of?

sweet [91]

When a substance is entering a phase change, the gain or loss of heat is a result of energy gained or lost in forming or breaking intermolecular interaction.

The constant temperatures occur when a substance is undergoing a phase transition. If heat is removed from a substance , such as in freezing and condensation , then the process is exothermic . In this instance , heat is decreasing the speed of the molecules causing then move slower.

In chemistry and thermodynamics, phase transitions (or phase changes) are the physical processes of transition between a state of a medium, identified by some parameters, and another one, with different values of the parameters.

Commonly the term is used to refer to changes among the basic states of matter: solid, liquid, and gas, as well as plasma in rare cases.

For example, a phase of a thermodynamic system and the states of matter have uniform physical properties. During a phase transition of a given medium, certain properties of the medium change, often discontinuously, as a result of the change of external conditions, such as temperature, pressure, or others.

For example, a liquid may become gas upon heating to the boiling point, resulting in an abrupt change in volume. The measurement of the external conditions at which the transformation occurs is termed the phase transition. Phase transitions commonly occur in nature and are used today in many technologies.

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8 0

2 years ago

It takes 24.56 mL of a sodium hydroxide solution to precisely neutralize 2.023 g of potassium hydrogen phthalate (F.W. = 204.22g

Alinara [238K]

Answer:

0.4033 M is the concentration of the sodium hydroxide solution.

Explanation:

Mass of potassium hydrogen phthalate = 2.023 g

Molar mass of potassium hydrogen phthalate = 204.22 g/mol

Moles of potassium hydrogen phthalate :

= $\frac{2.023 g}{204.22 g/mol}=0.009906 mol$

$C_8H_5KO_4+NaOH\rightarrow C_8H_4KO_4Na+H_2O$

According to reaction, 1 mole of potassium hydrogen phthalate reacts with 1mole of NaOH. Then 0.009906 moles of potassium hydrogen phthalate will recat with:

$\frac{1}{1}\times 0.009906 mol=0.009906 mol$ of NaOH

Moles of NaOH = 0.009906 mol

Volume of NaOH solution = 24.56 mL = 0.02456 L

$Molarity=\frac{Moles}{Volume (L)}$

$[NaOH]=\frac{0.009906 mol}{0.02456 L}=0.4033 M$

0.4033 M is the concentration of the sodium hydroxide solution.

8 0

3 years ago

Holds together Ca²⁺ and SO²⁻₄, Used by C atoms to complete their outermost energy level. __________ Is the main source of attrac

Fudgin [204]

Answer:

The correct answer is a. Hydrogen bonding.

Explanation:

The property by which water molecules attract each other is cohesion. groups of water molecules are formed by this interaction by adhesion with other water molecules.

Hydrogen bridges are great forces that hold water molecules together. They form a compact structure that gives it the property of being an almost incompressible liquid. These weak interactions are formed between a hydrogen with a positive partial charge and a more electronegative atom, such as oxygen.

Have a nice day!

4 0

4 years ago

15.0 mL of 0.050 M Ba(NO3)2 M and 100.0 mL of 0.10 M KIO3 are added together in a 250 mL erlenmeyer flask. In this problem, igno

timama [110]

Answer:

Yes, precipitation of barium iodate will occur.

Explanation:

Molarity of barium nitrate solution = 0.050 M

Volume of barium nitrate solution =15.0 mL = 0.0150 L

1 mL = 0.001 L

Moles of barium nitrate = n

$n=0.050 M\times 0.0150L=0.00075 mol$

$Ba(NO_3)_2(aq)\rightarrow Ba^{2+}(aq)+2NO_3^{-}(aq)$

Moles of barium ions: $1\times 0.00075 mol=0.00075 mol$

Molarity of potassium iodate solution = 0.10 M

Volume of potassium iodate solution =100.0 mL = 0.1000 L

1 mL = 0.001 L

Moles of potassium iodate = n'

$n'=0.10 M\times 0.1000 L=0.01 mol$

$KIO_3(aq)\rightarrow K^{+}(aq)+IO_3^{-}(aq)$

Moles of iodate ions = $1\times 0.01 mol=0.01 mol$

After mixing of both solution in 250 mL in erlenmeyer flask

Volume of the final solution = 250 mL = 0.250 L

Concentration of barium ions in 250 mL solution :

$[Ba^{2+}]=\frac{0.00075 mol}{0.250 L}=0.003 M$

Concentration of iodate ions:

$[IO_3^{-}]=\frac{0.01 mol}{0.250 L}=0.04 M$

Solubility product of barium iodate, $K_{sp}=4.01\times 10^{-9}$

Ionic product of the barium iodate in solution : $K_i$

$Ba(IO_3)_2\rightleftahrpoons Ba^{2+}+2IO_3^{-}$

$K_i=[Ba^{2+}][IO_2^{-}]^2$

$K_i=0.003 M\times (0.04 M)^2=4.8\times 10^{-6}$

$K_{sp}$ ( precipitation)

As we can see, the ionic product of the barium iodate is greater than the solubility product of the barium iodate precipitation of barium iodiate will occur in 250 mL of final solution.

5 0

4 years ago

Match the following equation with the type of chemical reaction. Question 6 options: H2 + O2 ---> H2O HBr ---> H2 + Br2 HC

kenny6666 [7]

Hello there!

1. Synthesis: 2H₂ + O₂ → 2H₂O
2. Decomposition: 2HBr → H₂ + Br₂
3. Single-Replacement: 2Al + 3H₂SO₄ → 3H₂ + Al₂(SO₄)₃
4. Double-Replacement: 2HCl + 2NaOH → 2H₂O + 2NaCl
5. Combustion: 2C₂H₆ + 7O₂ → 6H₂O + 4CO₂

I hope this helps!
Brady

5 0

3 years ago