Answer:
ΔH = +155.6 kJ
Explanation:
The Hess' Law states that the enthalpy of the overall reaction is the sum of the enthalpy of the step reactions. To do the addition of the reaction, we first must reorganize them, to disappear with the intermediaries (substances that are not presented in the overall reaction).
If the reaction is inverted, the signal of the enthalpy changes, and if its multiplied by a constant, the enthalpy must be multiplied by the same constant. Thus:
N₂(g) + O₂(g) → 2NO(g) ΔH = +180.7 kJ
2NO(g) + O₂(g) → 2NO₂(g) ΔH = -113.1 kJ
2N₂O(g) → 2N₂(g) + O₂(g) ΔH = -163.2 kJ
The intermediares are N₂ and O₂, thus, reorganizing the reactions:
N₂(g) + O₂(g) → 2NO(g) ΔH = +180.7 kJ
NO₂(g) → NO(g) + (1/2)O₂(g) ΔH = +56.55 kJ (inverted and multiplied by 1/2)
N₂O(g) → N₂(g) + (1/2)O₂(g) ΔH = -81.6 kJ (multiplied by 1/2)
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N₂O(g) + NO₂(g) → 3NO(g)
ΔH = +180.7 + 56.55 - 81.6
ΔH = +155.6 kJ
Answer:6.719Litres of Cl2 gas.
Explanation:According to eqn of rxn
2Na +Cl2=2NaCl
P=689torr=689/760=0.91atm
T=39°C+273=312K
according to stoichiometry of the reaction,1Moles of Cl2 gives 2moles of NaCl
But 28g of NaCl was given,we have to convert this to moles by using the relation, n=mass/MW
MW of NaCl=23+35.5=58.5g/mol
n=28g(mass given of NaCl)/58.5
n=0.479moles of NaCl
Going back to the reaction,
if 1moles of Cl2 produces 2moles of NaCl
x moles of Cl2 will give 0.479moles of NaCl.
x=0.479*1/2
x=0.239moles of Cl2.
To find the volume, we use ideal ggas eqn,PV=nRT
V=nRT/P
V=0.239*0.082*312/0.91
V=6.719Litres
<span>A solution with a pH of 4 has ten times the concentration of H</span>⁺<span> present compared to a solution with a pH of 5.
</span>pH <span>is a numeric scale for the acidity or basicity of an aqueous solution. It is the negative of the base 10 logarithm of the molar concentration of hydrogen ions.
</span>[H⁺] = 10∧-pH.
pH = 4 → [H⁺]₁ = 10⁻⁴ M = 0,0001 M.
pH = 5 → [H⁺]₂ = 10⁻⁵ M = 0,00001 M.
[H⁺]₁ / [H⁺]₂ = 0,0001 M / 0,00001 M.
[H⁺]₁ / [H⁺]₂ = 10.
a thin solid glass rod that is used in chemistry to combine substances. A stirring rod often has rounded ends and is about the length of a long straw.
<h3>What use serves the stirring rod?</h3>
A crucial component of lab apparatus for mixing chemicals and liquids for reactions is a long, thin stirring rod. Stirring rods are made of solid plastic, glass, or steel and are non-abrasive, chemically inert, and chemically resistant.
<h3>What is the name of the glass stirring rod?</h3>
Glass rod, also known as a stirring rod, stir rod, or solid glass rod, is frequently made of quartz and borosilicate glass. Its diameter and length can be modified to meet your needs.
<h3>Does filtration employ stirring rods?</h3>
When the liquid transfer procedure is paused, use a stirring rod to direct the liquid flow into the funnel and stop small amounts of liquid from dribbling down the beaker's outside.
learn more about stirring rod here
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<span>In order to solve this problem you must first make sure all your numbers are in like terms. From the density value you can see that it is grams per liter. The first conversion you must do in convert the 125.0 mL value to Liters which you would do by dividing by 1000 because 1 liter is equal to 1000 mL. 125.0 divided by 1000 is 0.125 Liter. Now you will use the density equation to solve. The density equation is density is equal to mass divided by volume. Plug in your known numbers for density and volume. Then solve for mass. So Density (1.269 g/l is equal to mass divided by volume (.125 Liter) You must rearrange the equation to multiple density by volume which is 1.269 times 0.125 which will give you 0.1586. Because the Liters cancel each other out, the answer's unit will be grams. Your final answer is 0.1586 grams.</span>
