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3 years ago

Which property could be used to identify an unknown substance?

1 answer:

5 0

Physical properties are those that can be determined or measured without changing the composition or identity of the substance. These properties include color, odor, taste, density, melting point, boiling point, conductivity, and hardness.

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Which type of salt would be most effective for melting ice on roads?

OLga [1]

Calcium Chloride is the salt that is effective for melting ice on roads

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4 years ago

Read 2 more answers

2-phosphoglycerate(2PG) is converted to phosphoenolpyruvate (PEP) by the enzyme enolase. The standard free energy change(deltaGo

pogonyaev

Answer:

The correct option is: (D) -2.4 kJ/mol

Explanation:

Chemical reaction involved: 2PG ↔ PEP

Given: The standard Gibb's free energy change: ΔG° = +1.7 kJ/mol

Temperature: T = 37° C = 37 + 273.15 = 310.15 K (∵ 0°C = 273.15K)

Gas constant: R = 8.314 J/(K·mol) = 8.314 × 10⁻³ kJ/(K·mol) (∵ 1 kJ = 1000 J)

Reactant concentration: 2PG = 0.5 mM

Product concentration: PEP = 0.1 mM

Reaction quotient: $Q_{r} =\frac{\left [ PEP \right ]}{\left [ 2PG \right ]} = \frac{0.1 mM}{0.5 mM} = 0.2$

To find out the Gibb's free energy change at 37° C (310.15 K), we use the equation:

$\Delta G = \Delta G^{\circ } + 2.303 R T log Q_{r}$

$\Delta G = 1.7 kJ/mol + [2.303 \times (8.314 \times 10^{-3} kJ/(K.mol))\times (310.15 K)] log (0.2)$

$\Delta G = 1.7 + [5.938] \times (-0.699) = 1.7 - 4.15 = (-2.45 kJ/mol)$

Therefore, the Gibb's free energy change at 37° C (310.15 K): ΔG = (-2.45 kJ/mol)

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3 years ago

What would be the best way to measure the volume of a small ?

WITCHER [35]

You can use a graduated cylinder.

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3 years ago

Chemistry an atom of strontium has at least four different isotopes. what is different between an isotope of 86sr and an isotope

lions [1.4K]

Isotopes are atoms of the same element that differ in the number of neutrons.

Remember that all the atoms of an element have the same number of protons. So the only difference between isotopes of an element is the number of neutrons.

86 Sr means that the mass number of this isotope is 86. Also, remember that the mass number is the number of protons plus the number of neutrons.

87 Sr means that the mass number of this isotope is 87.

So, 86 Sr and 87 Sr differ 1 neutron.

Answer: 1 neutron

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3 years ago

Which is also known as artificial (synthetic) silk

vodka [1.7K]

Answer:

Rayon is a synthetic fiber or man-made fiber or artificial fiber as it is prepared from the natural raw material called cellulose. ... The kind of rayon fibers which imitate the feel and texture of natural silk is therefore termed as 'artificial silk'.

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2 years ago