What is Hess‘s law please help

Chemistry

1 answer:

SCORPION-xisa [38]2 years ago

4 0

The correct answer is D. Hess's law states than the enthalpy of a reaction does not depend on the reaction path

Explanation:

In a chemical reaction, the enthalpy refers to the internal energy in a system and how this increases or decreases during the reaction. According to Hess's law proposed by German Hess in 1940, the enthalpy does not depend on the reaction path or the number of steps in a reaction. This means one reaction of only one step will have the same enthalpy that if the reaction occurs in several steps because the energy that requires all the process is the same. Thus, the "Hess's law states than the enthalpy of a reaction doe s not depend on the reaction path".

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15. In the image given below, magnesium metal is coiled as a thin ribbon. What property of metal is exhibited by it? A Ductility

Sholpan [36]

Answer: The property of magnesium that is exhibited by it is DUCTILITY. The correct option is A.

Explanation:

Magnesium is a member of the alkaline earth metals. It occurs in nature, only in the combined state, as Epsom salt, dolomite and in many trioxosilicates( IV) including talc and asbestos. They have the following physical properties:

--> Appearance: they are silvery-white solids

--> Relative density: It has a relative density of 1.74

--> DUCTILITY: it's very ductile in nature

--> melting point: it has a melting point of 660°C.

--> Conductivity: They are good conductor of heat and electricity.

Furthermore, DUCTILITY is the physical property of a metal associated with the ability to be hammered thin or stretched into wire without breaking. A metal such as magnesium can therefore be coiled as a thin ribbon without fracturing due to its ductile physical properties.

8 0

2 years ago

A sample of gas initially has a volume of 1.42 L at 293 K and 1.30 atm. What volume will the sample have if the pressure changes

worty [1.4K]

Answer:

1.35

Explanation:

5 0

2 years ago

Which substance has a coefficient of 2 when you balance the equation for this redox reaction? cu(s) + hno3(aq) → cu(no3)2(aq) +

Mama L [17]

In this redox reaction, the Cu goes from oxidation state of (0) to (+2), therefore it oxidises. N in HNO₃ goes from oxidation state of (+5) to N in NO with oxidation state of (+2) and becomes reduced.
Cu acts as the reducing reagent and HNO₃ is the oxidising agent.
oxidation half reaction
Cu ---> Cu²⁺ + 2e --1)
reduction half reaction
4H⁺ + 3e + NO₃⁻ ---> NO + 2H₂O --2)
to balance the number of electrons , 1) x3 and 2) x2
3Cu ---> 3Cu²⁺ + 6e
8H⁺ + 6e + 2NO₃⁻ ---> 2NO + 4H₂O
add the 2 equations
3Cu + 8H⁺ + 2NO₃⁻ ---> 3Cu²⁺ + 2NO + 4H₂O
add 6 nitrate ions to both sides to add up to 8 and form acid with 8H⁺ ions
3Cu + 8HNO₃ ---> 3Cu(NO₃)₂ + 2NO + 4H₂O
Balanced equation for the redox reaction is as follows;
3Cu(s) + 8HNO₃(aq) → 3Cu(NO₃)₂(aq) + 2NO(g) + 4H₂O<span>(l)

NO has a coefficient of 2

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8 0

3 years ago

I cant seem to figure out ANY of these... help when you can pls :.)

Nonamiya [84]

The first one is some reaction with water even I am studying the same

7 0

3 years ago

If the density of pure water is 0.9922 g/mL at 40 ºC, calculate its theoretical molarity at that temperature. Report to 4 sig fi

OleMash [197]

Answer is: theoretical molarity of water is 55.1222 mol/L.<span>
d(H</span>₂O) = 0.9922 g/mL.
M(H₂O) = 2 · Ar(H) + Ar(O) · g/mol.
M(H₂O) = 2 + 16 · g/mol = 18 g/mol.
c(H₂O) = d(H₂O) ÷ M(H₂O).
c(H₂O) = 0.9922 g/mL ÷ 18 g/mol.
c(H₂O) = 0.0551 mol/mL.
c(H₂O) = 0.0551 mol/mL · 1000 mL/L = 55.1222 mol/L.

3 0

3 years ago