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3 years ago

The characteristic properties of metals are associated with

Chemistry

1 answer:

Sedbober [7]3 years ago

8 0

Answer:

Explanation:

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An article in a magazine denies that Earth is warming and climate change is occurring. The writer reports that this season was t

ivann1987 [24]

First off, you should be looking at the whole world, not just the northeastern US. Are other regions warming? Can you provide proof that simply because the northeast received a lot of snow and low temperatures, climate change is not a viable theory?

6 0

3 years ago

Experiments with rats show that if rats are dosed with 3.0 mg/kg of cocaine (that is, 3.0 mg cocaine per kg of animal mass), the

Aliun [14]

Answer:

The molecules of dopamine would be produced in a rat after 60 seconds of a 3.0 mg/kg dose of cocaine is $2.258\times 10^{12} molecules$ .

Explanation:

Concentration of dopamine = 0.75 μM = $7.5\times 10^{-7} M$

1 μM = $10^{-6} M$

Volume of the brain in which dopamine is produced = $V=5.00 mm^3$

$1 mm^3=10^{-6} L$

$V = 5.00\times 10^{-6} L$

Moles of dopamine = n

$Concentration=\frac{moles}{Volume}$

$7.5\times 10^{-7} M=\frac{n}{5.00\times 10^{-6} L}$

$n=7.5\times 10^{-7} M\times 5.00\times 10^{-6} L=3.75\times 10^{-12} mol$

$1 mol = 6.022\times 10^{23} molecules$

So, molecules in $3.75\times 10^{-12} mol$ of dopamine :

$3.75\times 10^{-12}\times 6.022\times 10^{23}=2.258\times 10^{12} molecules$

4 0

3 years ago

Be sure to answer all parts. The standard enthalpy of formation and the standard entropy of gaseous benzene are 82.93 kJ/mol and

skelet666 [1.2K]

Answer : The values of $\Delta H^o,\Delta S^o\text{ and }\Delta G^o$ are $33.89kJ,95.94J/K\text{ and }5.299kJ/mol$ respectively.

Explanation :

The given balanced chemical reaction is,

$C_6H_6(l)\rightarrow C_6H_6(g)$

First we have to calculate the enthalpy of reaction $(\Delta H^o)$ .

$\Delta H^o=H_f_{product}-H_f_{reactant}$

$\Delta H^o=[n_{C_6H_6(g)}\times \Delta H_f^0_{(C_6H_6(g))}]-[n_{C_6H_6(l)}\times \Delta H_f^0_{(C_6H_6(l))}]$

where,

$\Delta H^o$ = enthalpy of reaction = ?

n = number of moles

$\Delta H_f^0_{(C_6H_6(g))}$ = standard enthalpy of formation of gaseous benzene = 82.93 kJ/mol

$\Delta H_f^0_{(C_6H_6(l))}$ = standard enthalpy of formation of liquid benzene = 49.04 kJ/mol

Now put all the given values in this expression, we get:

$\Delta H^o=[1mole\times (82.93kJ/mol)]-[1mole\times (49.04J/mol)]$

$\Delta H^o=33.89kJ/mol=33890J/mol$

Now we have to calculate the entropy of reaction $(\Delta S^o)$ .

$\Delta S^o=S_f_{product}-S_f_{reactant}$

$\Delta S^o=[n_{C_6H_6(g)}\times \Delta S^0_{(C_6H_6(g))}]-[n_{C_6H_6(l)}\times \Delta S^0_{(C_6H_6(l))}]$

where,

$\Delta S^o$ = entropy of reaction = ?

n = number of moles

$\Delta S^0_{(C_6H_6(g))}$ = standard entropy of formation of gaseous benzene = 269.2 J/K.mol

$\Delta S^0_{(C_6H_6(l))}$ = standard entropy of formation of liquid benzene = 173.26 J/K.mol

Now put all the given values in this expression, we get:

$\Delta S^o=[1mole\times (269.2J/K.mol)]-[1mole\times (173.26J/K.mol)]$

$\Delta S^o=95.94J/K.mol$

Now we have to calculate the Gibbs free energy of reaction $(\Delta G^o)$ .

As we know that,

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

At room temperature, the temperature is $25^oC\text{ or }298K$ .

$\Delta G^o=(33890J)-(298K\times 95.94J/K)$

$\Delta G^o=5299.88J/mol=5.299kJ/mol$

Therefore, the values of $\Delta H^o,\Delta S^o\text{ and }\Delta G^o$ are $33.89kJ,95.94J/K\text{ and }5.299kJ/mol$ respectively.

6 0

3 years ago

Read 2 more answers

A piece of wire contains 1.52x10^22 atoms of copper. Calculate the miles of copper in the wire

melamori03 [73]

Moles of Copper =

$1.52$ × $10^{22}atoms$ × $\frac{1 mol }{6.022 * 10^{23}atoms}$

= 0.0252 mol Cu

6 0

4 years ago

What mass of water is produced from the complete combustion of 7.10×10−3 g of methane? Express your answer with the appropriate

Ann [662]

Answer:

16 mg of water can be produced by 7.1×10⁻³ g of CH₄

Explanation:

This is the reaction:

CH₄ + 2O₂ → CO₂ + 2H₂O

In a combustion, oxgen is a reactant with another compound, and the products are always water and carbon dioxide

1 mol of methane can produce 2 moles of water. Ratio is 1:2

If we convert the mass to moles → 7.1×10⁻³ g . 1 mol/ 16g = 4.43×10⁻⁴ mol

In this reaction I would produce the double of moles I have from methane, so If I have 4.43×10⁻⁴ moles of methane I would produce 8.87×10⁻⁴ moles of water.

What mass of water, corresponds to 8.87×10⁻⁴ moles?

8.87×10⁻⁴ mol . 18g / 1mol = 0.016 g which is actually the same as 16 mg

6 0

4 years ago