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3 years ago

Please let me know if this is correct?

Chemistry

1 answer:

siniylev [52]3 years ago

6 0

Answer: Yes! you're all good. Alkali metals in group 1 are the most metallic :)

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What would happen to earth's orbit around the sun if there were gravity

kipiarov [429]

If the sun was not there the earth would travel in a straight line

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3 years ago

In a titration of 0.5 M HCl and an unknown concentration NaOH, 25.0 ml of NaOH was required to completely neutralize 25.0 ml of

baherus [9]

When an acid is neutralized by a base, that means moles of H+ = moles of OH-

moles of H+ = 0.5 M * 0.025 L HCl = 0.0125 moles H+

moles of OH- should be equal to 0.0125 moles, so
0.0125 moles = (x) * 0.025 L NaOH

x is the concentration of NaOH, which we want to find.

x = 0.5 M

The correct answer is C) 0.5 M.

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3 years ago

Three kilograms of steam is contained in a horizontal, frictionless piston and the cylinder is heated at a constant pressure of

lakkis [162]

Answer:

Final temperature: 659.8ºC

Expansion work: 3*75=225 kJ

Internal energy change: 275 kJ

Explanation:

First, considering both initial and final states, write the energy balance:

$U_{2}-U_{1}=Q-W$

Q is the only variable known. To determine the work, it is possible to consider the reversible process; the work done on a expansion reversible process may be calculated as:

$dw=Pdv$

The pressure is constant, so: $w=P(v_{2}-v_{1} )=0.5*100*1.5=75\frac{kJ}{kg}$ (There is a multiplication by 100 due to the conversion of bar to kPa)

So, the internal energy change may be calculated from the energy balance (don't forget to multiply by the mass):

$U_{2}-U_{1}=500-(3*75)=275kJ$

On the other hand, due to the low pressure the ideal gas law may be appropriate. The ideal gas law is written for both states:

$P_{1}V_{1}=nRT_{1}$

$P_{2}V_{2}=nRT_{2}\\V_{2}=2.5V_{1}\\P_{2}=P_{1}\\2.5P_{1}V_{1}=nRT_{2}$

Subtracting the first from the second:

$1.5P_{1}V_{1}=nR(T_{2}-T_{1})$

Isolating $T_{2}$ :

$T_{2}=T_{1}+\frac{1.5P_{1}V_{1}}{nR}$

Assuming that it is water steam, n=0.1666 kmol

$V_{1}=\frac{nRT_{1}}{P_{1}}=\frac{8.314*0.1666*373.15}{500} =1.034m^{3}$

$T_{2}=100+\frac{1.5*500*1.034}{0.1666*8.314}=659.76$ ºC

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3 years ago

Which of these characteristics best describes a basic solution?

mario62 [17]

I believe the correct answer would be that it feels slippery. Being slippery or soapy is one characteristic of a base. This due to the fact that it dissolves the oils and fatty acids from the skin. Other characteristics would be that it turns litmus paper blue and has a bitter taste.

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3 years ago

The principle of conservation of mass is satisfied in a chemical equation when

avanturin [10]

The products have the same mass as the reactants

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3 years ago