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3 years ago

What would indicate that a physical change takes place when copper is drawn into wire

Chemistry

2 answers:

dedylja [7]3 years ago

5 0

The shape of the copper would change.

kykrilka [37]3 years ago

5 0

Explanation:

A physical change is defined as a change that does not bring any difference in chemical composition of a substance.

For example, shape, size, mass, volume, density, etc of a substance are all physical properties.

So, when copper is drawn into wire then there will occur change in its shape but there will not be any change in its chemical composition.

Whereas when a change in chemical composition of a substance occurs then it is known as a chemical change.

Hence, we can conclude that change in the shape of copper when it is drawn into wire indicates a physical change.

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Consider a reaction that has a positive ΔH and a positive ΔS. Which of the following statements is TRUE?A) This reaction will be

Alja [10]

Answer: A) This reaction will be spontaneous only at high temperatures

Explanation:

$\Delta G$ = +ve, reaction is non spontaneous

$\Delta G$ = -ve, reaction is spontaneous

$\Delta G$ = 0, reaction is in equilibrium

Using Gibbs Helmholtz equation:

$\Delta G=\Delta H-T\Delta S$

Given : $\Delta H=+ve$

$\Delta S=+ve$

$\Delta G=(+ve)-T(+ve)$

$\Delta G=(+ve)(-ve)$

Thus the value of $\Delta G$ is negative and spontaneous when temperature is high.

4 0

3 years ago

Is iornIInitrate ionic or covalent

kondaur [170]

Answer:

Iron (II) nitrate is ionic compound

Explanation:

Formula:

Fe(NO₃)₂

Iron (II) nitrate is ionic compound.

Its molecular mass is 179.85 g/mol.

NO⁻₃ is anion while Fe⁺² is cation.

Iron loses its two electron which is accepted by nitrate.

Its molecular formula can be written as FeN₂O₆.

Its color is pale green.

Its melting point is 333.65 K.

It is para magnetic compound.

it is mostly present in non hydrated form.

It is also known as ferric nitrate.

It is used to form sodium amide.

Its is also used catalyst.

7 0

3 years ago

Acetic acid has a pKa of 4.74. Buffer A: 0.10 M HC2H3O2, 0.10 M NaC2H3O2 Buffer B: 0.30 M HC2H3O2, 0.30 M NaC2H3O2 Buffer C: 0.5

e-lub [12.9K]

Answer:

Buffer B has the highest buffer capacity.

Buffer C has the lowest buffer capacity.

Explanation:

An effective weak acid-conjugate base buffer should have pH equal to $pK_{a}$ of the weak acid. For buffers with the same pH, higher the concentrations of the components in a buffer, higher will the buffer capacity.

Acetic acid is a weak acid and $CH_{3}COO^{-}$ is the conjugate base So, all the given buffers are weak acid-conjugate base buffers. The pH of these buffers are expressed as (Henderson-Hasselbalch):

$pH=pK_{a}(CH_{3}COOH)+log\frac{[CH_{3}COO^{-}]}{[CH_{3}COOH]}$

$pK_{a}(CH_{3}COOH)=4.74$

Buffer A: $pH=4.74+log(\frac{0.10}{0.10})=4.74$

Buffer B: $pH=4.74+log(\frac{0.30}{0.30})=4.74$

Buffer C: $pH=4.74+log(\frac{0.10}{0.50})=4.04$

So, both buffer A and buffer B has same pH value which is also equal to $pK_{a}$ . Buffer B has higher concentrations of the components as compared to buffer A, Hence, buffer B has the highest buffer capacity.

The pH of buffer C is far away from $pK_{a}$ . Therefore, buffer C has the lowest buffer capacity.

6 0

3 years ago

A chemist carefully measures the amount of heat needed to raise the temperature of a 894.0g sample of a pure substance from to −

astraxan [27]

Answer:

C = 0.2349 J/ (g °C)

Explanation:

Mass, m = 894.0g

Initial Temperature = −5.8°C

Final Temperature = 17.5°C

Temperature change = 17.5°C - (−5.8°C) = 23.3

Heat, H = 4.90kJ = 4900 J

Specific heat capacit, C = ?

The relationship between these quantities is given by the equation;

H = mCΔT

C = H / mΔT

C = 4900 / (894)(23.3)

C = 0.2349 J/ (g °C)

4 0

3 years ago

Which of the following values is measured the LEAST precisely? * 22mL 45.2mL 50mL 100mLchem

nekit [7.7K]

Answer:

If you're looking at the data as a whole, it would most likely be 100ml.

Explanation: The definition of precise is data close together so 100ml is furthest away from the other recorded numbers

7 0

3 years ago