Answer:
Option B = atomic number
Explanation:
Electrically neutral atom:
An electrically neutral atom have equal number of protons and neutrons. In other words we can say that negative and positive charges are equal in magnitude and cancel the each other. For example if neutral atom has 6 protons than it must have 6 electrons. The number of protons or number of electrons are the atomic number of an atom while the number of protons and number of neutrons are the mass number of an atom. Every atom consist of nucleus or a positive center. The protons and neutrons are present with in the nucleus while electrons are present out side the nucleus. All these three subatomic particles construct an atom.
Example:
Consider the example of carbon. It consist of six protons and six electrons. So, its atomic number is six. While the six neutrons are also present in nucleus with six protons that’s why its mas number is 12.
Electron:
The electron is subatomic particle that revolve around outside the nucleus and has negligible mass. It has a negative charge.
Symbol= e⁻
Mass= 9.10938356×10⁻³¹ Kg
It was discovered by j. j. Thomson in 1897 during the study of cathode ray properties.
Neutron and proton:
While neutron and proton are present inside the nucleus. Proton has positive charge while neutron is electrically neutral. Proton is discovered by Rutherford while neutron is discovered by James Chadwick in 1932.
Symbol of proton= P⁺
Symbol of neutron= n⁰
Mass of proton=1.672623×10⁻²⁷Kg
Mass of neutron=1.674929×10⁻²⁷ Kg
True!
population increases if the number of individuals. the population is the nuber of individuals
Answer:
See explanation
Explanation:
According to Newton's second law, the rate of change of momentum is proportional to the impressed force.
Mathematically;
Ft = mv - mu
Where;
F = Force
t = time
m= mass
v = final velocity
u = initial velocity
Since the mass is the same, the equation reduces to;
Ft = m(v-u)
So
F= m(v-u)/t
but
(v-u)/t = acceleration (a)
F = ma
a = F/m
Since the mass is the same because Sarah is the same size as i am but she pulls with a greater force, it follows that i will be the one in the wagon when the wagon has the greatest acceleration because the force that Sarah applies when pulling me is greater than the force i will apply when pulling her.
Answer:
A. 7.2%
B. 8.6 ppm
Explanation:
<em>Part A</em>
First let's <em>calculate the mass of I₂</em>, using the known value of moles and the molecular weight (253.8 g/mol)
- 4.0x10⁻² mol I₂ * 253.8 g/mol = 10.152 g I₂
Mass percentage is calculated using the mass of I₂ and the total mass (mass of I₂ + mass of CCl₄)
- Total mass = 130 + 10.152 = 140.152 g
- Mass percentage I₂ = 10.152 / 140.152 * 100 = 7.2%
<em>Part B</em>
The concentration of Sr⁺² in ppm is calculated using the formula
We're given the mass of Sr⁺² in grams, so now we <u>convert it into mg</u>:
- 8.2x10⁻³g *
= 8.2 mg
Now to convert kg of water into L, we use the density of seawater (1050 kg/m³):
<em>Converting density</em>: 1050 
* 
= 1.05 kg/L
- Volume of one kilogram of water = 1kgWater ÷ 1.05 kg/L = 0.95 L
Finally we<u> calculate the concentration of Sr⁺²</u>:
- 8.2 mg / 0.95 L = 8.6 ppm
In chemistry the need for standards when measuring quantities are in place for accurate measurement that is recognized world wide. This way, no matter what language people use, they will always understand there standards.
