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3 years ago

Please help fast! I will give brainliest!

Chemistry

1 answer:

Artemon [7]3 years ago

3 0

Explanation:

- 186 kj your answer

please mark,

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The basic repeating structural unit of a crystalline solid is called a _____. cell unit base unit unit cell lattice

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Unit Cell is the basic <span>repeating structural unit of a crystalline solid .</span>

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3 years ago

The specific heat of wood is 2.03 J/g.°C. How much

Brilliant_brown [7]

Answer:

11419 J/g/ 11.419 KJ/g

Explanation:

H=MCQ

H=225×2.03×(-15-10)

H=225×2.03(25) Note; negative sign is of no use

H=11419J/g

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the half life for strontium-90 is 29 years. how many half-lives did the sample go through at the end of 87 year

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2 years ago

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20 POINTS I will give brainliest to whoever answers correctly

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3 years ago

The standard enthalpy change for the following reaction is 873 kJ at 298 K.

Flura [38]

Answer: - 436.5 kJ.

Explanation:

According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.

According to this law, the chemical equation can be treated as ordinary algebraic expression and can be added or subtracted to yield the required equation.

The given chemical reaction is,

$2KCl(s)\rightarrow 2K(s)+Cl_2(g)$ $\Delta H_1=873kJ$

Now we have to determine the value of $\Delta H$ for the following reaction i.e,

$K(s)+\frac{1}{2}Cl_2(g)\rightarrow KCl(s)$ $\Delta H_2=?$

According to the Hess’s law, if we divide the reaction by half then the $\Delta H$ will also get halved and on reversing the reaction , the sign of enthlapy changes.

So, the value $\Delta H_2$ for the reaction will be:

$\Delta H_2=\frac{1}{2}\times (-873kJ)$

$\Delta H_2=-436.5kJ$

Hence, the value of $\Delta H_2$ for the reaction is -436.5 kJ.

8 0

3 years ago