ΔH for the reaction below is -826.0 kJ/mol. Calculate the heat change when a 69.03-g sample of iron is reacted.4Fe(s) + 3 O2(g)
1 answer:
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Answer:
m = 0.659 ounce
Explanation:
It is given that,
The thickness of a Teflon coating is, d = 1 mm
Area of the coating, A = 36 inch²
The density of Teflon, d = 0.805 g/mL
We need to find ounces of Teflon are needed.
Firstly, find the volume of the Teflon needed,
1 inch² = 6.4516 cm²
36 inch² = 232.258 cm²
Density,
V is volume of the Teflon needed, V = Ad
So,
Also, 1 gram = 0.035274 ounce
18.69 gram = 0.659 ounce
So, 0.659 ounces of Teflon are needed.
Answer : The balanced chemical equation in acidic medium will be,
Explanation :
Redox reaction or Oxidation-reduction reaction : It is defined as the reaction in which the oxidation and reduction reaction takes place simultaneously.
Oxidation reaction : It is defined as the reaction in which a substance looses its electrons. In this, oxidation state of an element increases. Or we can say that in oxidation, the loss of electrons takes place.
Reduction reaction : It is defined as the reaction in which a substance gains electrons. In this, oxidation state of an element decreases. Or we can say that in reduction, the gain of electrons takes place.
Rules for the balanced chemical equation in acidic solution are :
First we have to write into the two half-reactions.
Now balance the main atoms in the reaction.
Now balance the hydrogen and oxygen atoms on both the sides of the reaction.
If the oxygen atoms are not balanced on both the sides then adding water molecules at that side where the less number of oxygen are present.
If the hydrogen atoms are not balanced on both the sides then adding hydrogen ion at that side where the less number of hydrogen are present.
Now balance the charge.
The given chemical reaction is,
The oxidation-reduction half reaction will be :
Oxidation :
Reduction :
First balance the main element in the reaction.
Oxidation :
Reduction :
Now balance oxygen atom on both side.
Oxidation :
Reduction :
Now balance hydrogen atom on both side.
Oxidation :
Reduction :
Now balance the charge.
Oxidation :
Reduction :
The charges are not balanced on both side of the reaction. Thus, we are multiplying oxidation reaction by 2 and the adding both equation, we get the balanced redox reaction.
Oxidation :
Reduction :
The balanced chemical equation in acidic medium will be,
Answer:
The range of atoms = (30-300 pm) depending upon the element
Explanation:
The Atomic radii of the atom is the distance from the center of the circle to the outermost orbital.
The center of the circle is the nucleus and the radii is the outermost boundary.
The actual size of the atom is decided on the basis of the Zeff . Also known as <em>effective nuclear charge.</em>
<em>Zeff: It is the net positive charge felt by the outermost electron by the nucleus.</em>
<em>The value of Zeff depends upon the shielding constant. More the shielding less will be the Zeff . Hence the size of the atom increases.</em>
Due to shielding the outermost electrons feel less pull of nucleus.
<em>The greater the Zeff , the smaller the radius of the atom.</em>
The formula used to calculate the atomic mass is :
pm
Here "pm"= picometers
<u>The size of the smallest atom H-atom = 120 pm</u>
<u>The range of atoms = (30-300 pm)</u>