Answer:
Explanation:
In Polystrene, the molecular formula for the repeat unit = 
;
and the atomic weights of Carbon C = 12.01 g/mol
For Hydrogen, it is 1.01 g/mol
Hence, the repeat unit molecular weight is:
m = 8 (12.01 g/mol)+8(1.01 g/mol)
m = 96.08 g/mol + 8.08 g/mol
m = 104.16 g/mol
The degree of polymerization = no-average molecular weight/repeat unit molecular weight.
Mathematically;
<u>Answer:</u>
2.0158 grams
<u>Explantion:</u>
We are to find the mass of the hydrogen atoms in 1 mole of water.
We know that the formula of water is: 
We can see, from the above mentioned formula, that water has 2 hydrpgen atoms.
From the periodic table, we get to know that Hydrogen has an atomic mass of 1.00794 grams.
As there are 2 atoms of hydrogen in water so 
grams is the answer
Answer:
28.75211 kj
Explanation:
Given data:
Mass of iron bar = 841 g
Initial temperature = 84°C
Final temperature = 7°C
Heat released = ?
Solution:
Specific heat capacity:
It is the amount of heat required to raise the temperature of one gram of substance by one degree.
specific heat capacity of iron is 0.444 j/g.°C
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
ΔT = 7°C - 84°C
ΔT = -77°C
By putting values,
Q = 841 g × 0.444 j/g.°C × -77°C
Q = 28752.11 j
In Kj:
28752.11 j × 1 kJ / 1000 J
28.75211 kj
In an atom, the number of neutrons determines most specifically the isotopes of an element.
<h2>Further Explanation</h2><h3>An atom </h3>
- An atom is defined as the smallest particle of an element that can take part in a chemical reaction.
- Atoms are made of energy shells and the inner nucleus.
- It is also made up of subatomic particles, protons and neutrons.
<h3>Neutrons </h3>
- They are sub-atomic particles in an atom that are found in the nucleus of an atom. They have a zero charge or no charge.
- Neutrons are slightly heavier than protons.
- The number of protons and neutrons in a nucleus of an atom results to the atomic mass number of an atom. Like protons they only take part in nuclear reactions.
<h3>Protons</h3>
- Protons are subatomic particles that are found in the nucleus of an atom. They are positively charged. with a charge of +1.
- The number of protons differ from one element to another and thus used as the atomic number of an individual element.
- The nucleus of an atom is positively charged due to the positive charge of the protons.
- Additionally, protons do not take part in chemical reactions but in nuclear reactions.
<h3>Electrons </h3>
- They are found orbiting the nucleus on energy shells based on Clouds’ theory. Electrons are negatively charged each with a charge of -1.
- The number of electrons and protons in a neutral atom are equal. Additionally they have the least mass of the three sub-atomic particles.
- Electrons are the only sub-atomic particles that take part in chemical reactions.
<h3>Isotopes </h3>
- Isotopes are atoms of the same element that have the same mass number but different atomic number.
<h3>Mass number;</h3>
- Mass number is the sum of the number of protons and neutrons in the nucleus of an atom of an element.
Keywords: Atom, sub-atomic particles, electrons, protons, neutrons, isotopes
<h3>Learn more about:</h3>
Level: High school
Subject: Chemistry
Topic: Atomic structure
