How can you tell whether a substance is a binary compound

How does the A Hreaction relate to the A He of molecules involved in a reaction?

igor_vitrenko [27]

Answer:

B. ΔHreaction = ΔH°f reactants- ΔH°f products

Explanation:

<em>Using Hess's law, it is possible to sum ΔH of several related reactions to find ΔH of a particular reaction</em>.

Having in mind Hess's law, ΔH°f is defined as the change in enthalpy during the formation of 1 mole of substance from its constituent elements (That is, pure elements, mono or diatomics, that have a ΔH° = 0).

For example, in ΔH°f of H₂O, the equation is:

H₂(g) + 1/2O₂(g) → H₂O(g)

The constituent elements with ΔH°f = 0 are H₂(g) and O₂(g).

Now, using Hess's law, you can sum the ΔH°f of substance in a reaction as, for example:

NaOH + HCl → H₂O + NaCl. ΔHr

The ΔH°f for each substance in the reaction is:

NaOH: Na + 1/2H₂ + 1/2O₂ → NaOH <em>(1)</em>

HCl: 1/2H₂ + 1/2Cl₂ → HCl <em>(2)</em>

H₂O: H₂ + 1/2O₂ → H₂O <em>(3)</em>

NaCl: Na + 1/2Cl₂ → NaCl <em>(4)</em>

The algebraic sum of (3) + (4) is -(ΔH°f reactants):

H₂ + 1/2O₂ + Na + 1/2Cl₂ → NaCl + H₂O ΔH°f reactants

This reaction - {(1)+(2)} ΔH°f products

NaOH + HCl → H₂O + NaCl.

ΔHr = ΔH°f reactants- ΔH°f products

In the example, we obtain this relationship that can be expanded for all reactions. Thus, right answer is:

<h3>B. ΔHreaction = ΔH°f reactants- ΔH°f products</h3>

8 0

3 years ago

A chemist wants to examine specific chemical reactions and isolate certain products using a controlled experiment. How would the

professor190 [17]

Answer:

in a laboratory

Explanation:

A controlled experiment refers to the one where everything is an experiment except a single variable is held constant. A collection of information is typically taken as a control group, which is generally the ordinary state, and another group is analyzed( such as chemical reaction as per the question) in which all conditions are similar to the control group except for the variable under examination. The main benefit of a controlled experiment is that confusion over the accuracy of the results can be eliminated more easily.

6 0

3 years ago

• What policies might people put in place to conserve water levels in lakes and aquifers?

vladimir2022 [97]

Some policies they might do is to put limits on water usage, like making sure that people don't use too much water in baths and when they are tending to their gardens.

7 0

4 years ago

What is packing fraction ?<br>state the formula used to calculate it.<br><br>thankyou ~

slava [35]

Answer:

<h2><em>please</em><em> </em><em>mark</em><em> </em><em>me</em><em> </em><em>brainliest</em></h2>

Explanation:

<h2>Packing fraction is defined as a way of expressing the variation of isotopic mass from whole mass number (atomic mass). This fraction can have positive or can have negative sign. A positive packing fraction describes a tendency towards instability.</h2><h2>The equation for packing fraction is: Packing fraction = (N atoms) x (V atom) / V unit cell. N atoms is the number of atoms in a unit cell. V atom is the volume of the atom, and V unit cell is the volume of a unit cell. Substitute the number of atoms per unit cell into the equation.</h2>

6 0

3 years ago

The _______ of a wave is a measure of the amount of energy it carries

Bumek [7]

The word that best fits is frequency. The sentence is The frequency of a wave is a measure of the amount of energy it carries. There is a direct relationship between frequency and energy of a wave. The constant of proportionality is h, Planck's constant. So, Energy = h * frequency. So, the answer is frequency.<span> Although you should know that wavelength is related to frequency and so it is also a measure of the amount of energy and it should also be other valid answer.</span>

6 0

3 years ago