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3 years ago

When physical properties are measured their identity will be changed. True or False

Chemistry

1 answer:

wolverine [178]3 years ago

5 0

Answer:

False

Explanation:

A physical change is a change to a sample of matter in which some properties of the material change, but the identity of the matter does not.

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a block of wood has a density of 0.95 g/cm3. will it float or sink when placed on a liquid with a density of 0.88 g/mL? explain

vesna_86 [32]

Since 1mL=1cm^3 the wood would sink due to it being more dense. I.e. 0.95>0.88

3 0

3 years ago

Read 2 more answers

Calculate the standard reaction Gibbs free energy for the following cell reactions: (a) 2 Ce41(aq) 1 3 I2(aq) S 2 Ce31(aq) 1 I32

Law Incorporation [45]

Answer:

For a: The standard Gibbs free energy of the reaction is -347.4 kJ

For b: The standard Gibbs free energy of the reaction is 746.91 kJ

Explanation:

Relationship between standard Gibbs free energy and standard electrode potential follows:

$\Delta G^o=-nFE^o_{cell}$ ............(1)

For a:

The given chemical equation follows:

$2Ce^{4+}(aq.)+3I^{-}(aq.)\rightarrow 2Ce^{3+}(aq.)+I_3^-(aq.)$

Oxidation half reaction: $Ce^{4+}(aq.)\rightarrow Ce^{3+}(aq.)+e^-$ ( × 2)

Reduction half reaction: $3I^_(aq.)+2e^-\rightarrow I_3^-(aq.)$

We are given:

$n=2\\E^o_{cell}=+1.08V\\F=96500$

Putting values in equation 1, we get:

$\Delta G^o=-2\times 96500\times (+1.80)=-347,400J=-347.4kJ$

Hence, the standard Gibbs free energy of the reaction is -347.4 kJ

For b:

The given chemical equation follows:

$6Fe^{3+}(aq.)+2Cr^{3+}+7H_2O(l)(aq.)\rightarrow 6Fe^{2+}(aq.)+Cr_2O_7^{2-}(aq.)+14H^+(aq.)$

Oxidation half reaction: $Fe^{3+}(aq.)\rightarrow Fe^{2+}(aq.)+e^-$ ( × 6)

Reduction half reaction: $2Cr^{2+}(aq.)+7H_2O(l)+6e^-\rightarrow Cr_2O_7^{2-}(aq.)+14H^+(aq.)$

We are given:

$n=6\\E^o_{cell}=-1.29V\\F=96500$

Putting values in equation 1, we get:

$\Delta G^o=-6\times 96500\times (-1.29)=746,910J=746.91kJ$

Hence, the standard Gibbs free energy of the reaction is 746.91 kJ

7 0

3 years ago

A 0.533 g sample of a carbonate salt is added to a flask. The only thing you know is that per formula unit, there is only one ca

dimulka [17.4K]

Answer:

$\mathbf{CrCO_3}$

Explanation:

The total mole of $H_2SO_4$ added = 15 × 1 × 10⁻³

= 15 × 10⁻³ mole

= 15 mmoles

the number of moles of NaOH added in order to neutralize the excess acid = 0.5905 × 29.393 = 17.36 mmoles

the equation for the reaction is:

2NaOH + $H_2SO_4$ --------> $Na_2SO_4 +2H_2O$

i.e

2 moles of NaOH react with $H_2SO_4$

1 moles of NaOH will react with 1/2 $H_2SO_4$

17.36 mmoles of NaOH = 1/2 × 17.36 mmoles of $H_2SO_4$

= 8.68 mmoles

Number of moles of $H_2SO_4$ that react with MCO₃ = Total moles of $H_2SO_4$ added - moles of $H_2SO_4$ reacted with NaOH

= (15 - 8.68) mmoles

= 6.32 mmoles

$H_2SO_4$ + $MCO_3$ ------> $M_2SO_4$ + $H_2O$ + $CO_2$

1 mole of $H_2SO_4$ react with 1 mole of $MCO_3$

6.32 mmoles of $H_2SO_4$ = 6.32 mmoles of $MCO_3$

number of moles of $MCO_3$ = 6.32 10⁻³ moles

mass of $MCO_3$ (carbonate salt) = 0.533 g

molar mass of $MCO_3$ = (M+60)g/mol

We all know that ;

number of moles = mass/molar mass

Then:

6.32 10⁻³ = 0.533 / (M+60)

(M+60) = 0.533/ 6.32 10⁻³

M + 60 = 84.34

M = 84.34 - 60

M = 24.34

Thus the element with the atomic mass of 24.34 is Chromium

The chemical formula for the compound is : $\mathbf{CrCO_3}$

6 0

3 years ago

For each molecule of glucose processed during glycolysis, the net yield is ____.

olga nikolaevna [1]

(Starch) I hope this helps you please check again i'am not sure of my answer

3 0

3 years ago

Where are electrons found in an atom

dedylja [7]

Answer:

The electrons are found on the outer shell of the atom.

Explanation:

6 0

3 years ago

When physical properties are measured their identity will be changed. True or False​

When physical properties are measured their identity will be changed. True or False