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3 years ago

When using a crucible and lid, why must the crucible and lid be inspected for cracks before using?

Chemistry

2 answers:

kicyunya [14]3 years ago

7 0

If it has cracks it can shatter during heating due to temperature change.

Nana76 [90]3 years ago

3 0

Explanation:

A crucible and lid plays an important role in carrying out a reactions as they help the container or vessel to be tightly closed so the no other gases from the atmosphere can enter the vessel.

Moreover, it helps in maintaining the temperature of vessel.

Therefore, when the crucible and lid be inspected for cracks before using then it should not be used because during the reaction it is possible that it will break.

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I2(g) + Cl2(g)2ICl(g) Using standard thermodynamic data at 298K, calculate the entropy change for the surroundings when 1.62 mol

galina1969 [7]

Answer:

The change in entropy of the surrounding is -146.11 J/K.

Explanation:

Enthalpy of formation of iodine gas = $\Delta H_f_{(I_2)}=62.438 kJ/mol$

Enthalpy of formation of chlorine gas = $\Delta H_f_{(Cl_2)}=0 kJ/mol$

Enthalpy of formation of ICl gas = $\Delta H_f_{(ICl)}=17.78 kJ/mol$

The equation used to calculate enthalpy change is of a reaction is:

$\Delta H_{rxn}=\sum [n\times \Delta H_f(product)]-\sum [n\times \Delta H_f(reactant)]$

For the given chemical reaction:

$I_2(g)+Cl_2(g)\rightarrow 2ICl(g),\Delta H_{rxn}=?$

The equation for the enthalpy change of the above reaction is:

$\Delta H_{rxn}=[(2\times \Delta H_f_{(ICl)})]-[(1\times \Delta H_f_{(I_2)})+(1\times \Delta H_f_{(Cl_2)})]$

$=[2\times 17.78 kJ/mol]-[1\times 0 kJ/mol+1\times 62.436 kJ/mol]=-26.878 kJ/mol$

Enthaply change when 1.62 moles of iodine gas recast:

$\Delta H= \Delta H_{rxn}\times 1.62 mol=(-26.878 kJ/mol)\times 1.62 mol=-43.542 kJ$

Entropy of the surrounding = $\Delta S^o_{surr}=\frac{\Delta H}{T}$

$=\frac{-43.542 kJ}{298 K}=\frac{-43,542 J}{298 K}=-146.11 J/K$

1 kJ = 1000 J

The change in entropy of the surrounding is -146.11 J/K.

4 0

3 years ago

What is the mass in grams of 2.00 10 5 atoms of naturally occurring neon

lesantik [10]

Answer:

2.00X10^5 x 20gNe/6.02x10^23=6.46x10^-18 but books answer is 797.

Explanation:

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3 years ago

What is an abiotic factor in a squirrel's habitat that could be harmful if the factor changed

krek1111 [17]

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3 years ago

Which of the following is a possible genotype for the offspring

Mademuasel [1]

Answer:

Explanation:

The genotype of an organism is the combination of alleles it has at a particular locus. In contrast, the phenotype is the observable characteristics that are produced by the genotype.

B and D are phenotypes, and are therefore not possible genotypes.

In a cross between tt ff and TT FF, the only alleles that tt ff can pass on are t/f, and the only alleles TT FF can pass on are T/F. Therefore, the only possible genotype is Tt Ff

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Jobisdone [24]

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