Chemistry, 19.02.2020 05:55 who0fade

A chemist measures the energy change during the following reaction: 1. This reaction is:. a. endothermic. b. exothermic. 2. Suppose 70.1 g of NO2 react. Will any heat be released or absorbed? A. Yes, absorbed. B. Yes, released. C. No. 3. If you said heat will be released or absorbed, calculate how much heat will be released or absorbed?

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Answer from: lzzupboi

The question is incomplete. the complete question is:

A chemist measures the energy change during the following reaction: $2NO_2(g)\rightarrow N_2O_4$ $\Delta H=-55.3kJ$ 1. This reaction is:______. a. endothermic. b. exothermic.

2. Suppose 70.1 g of NO2 react. Will any heat be released or absorbed? A. Yes, absorbed. B. Yes, released. C. No.

3. If you said heat will be released or absorbed, calculate how much heat will be released or absorbed?

1. b. exothermic

2. Yes , released

3. 42.0 kJ

Explanation:

1. Endothermic reactions are those in which heat is absorbed by the system and exothermic reactions are those in which heat is released by the system.

$\Delta H$ for Endothermic reaction is positive and $\Delta H$ for Exothermic reaction is negative.

2. $2NO_2(g)\rightarrow N_2O_4$ $\Delta H=-55.3kJ$

According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number $6.023\times 10^{23}$ of particles.

To calculate the moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text {Molar mass}}=\frac{70.1g}{46g/mol}=1.52moles$

2 moles of NO_2 reacts, energy released = 55.3 kJ

1.52 moles of NO_2 reacts, energy released = $\frac{55.3 kJ}{2}\times 1.52=42.0kJ$

Thus 42.0 kJ heat will be released when 70.1 g of NO_2 react.

Answer from: Quest

A. volume stays constant. just took took the quiz

Answer from: Quest

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.

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