A cell membrane
B mitochondrion
C chloroplast
D cell wall
Answer:
Explanation:
Half life is the time taken to reduce the original concentration of the reactants to half.
Now, the number of half lives is related to the amount left after decomposition by the formula:
where,
a = amount of reactant left after n-half lives = ?
= Initial amount of the reactant
n = number of half lives = 5
Putting values in above equation, we get:
Thus the amount of sample that remains after 5 half lives is of original amount.
Red blood cells are primarily formed in the bone marrow, specifically the red bone marrow. The process of producing these cells, known as hematopoiesis, begins at the embryonic stage and continues throughout a person's life, with adult hematopoiesis being largely restricted to certain bones in the body. New red blood cells are continuously produced due to their relatively short lifespan.
Red blood cells are formed in the bone marrow, specifically in the red bone marrow which is a loose collection of cells where hematopoiesis or the production of blood cells occurs. This crucial process of forming blood cells, including red blood cells, is introduced in the embryonic stage in the yolk sac. However, as the embryo develops, this function is taken over by the spleen, liver, and lymph nodes, with the bone marrow eventually assuming most hematopoietic functions. The red blood cells, along with white blood cells and platelets, are all produced in the red bone marrow.
In children, this process can occur in the cavity of long bones, but in adults, it is largely restricted to certain bones such as the cranial and pelvic bones, the vertebrae, the sternum, and parts of the femur and humerus. The lifespan of these cells is relatively brief, so new ones must be continuously produced to maintain healthy bodily functions.
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b. metals.
c. halogens.
d. noble gases.
The elements that do not ordinarily form compounds are noble gases as they have complete octet.
An element is defined as a substance which cannot be broken down further into any other substance. Each element is made up of its own type of atom. Due to this reason all elements are different from one another.
Elements can be classified as metals and non-metals. Metals are shiny and conduct electricity and are all solids at room temperature except mercury. Non-metals do not conduct electricity and are mostly gases at room temperature except carbon and sulfur.
The number of protons in the nucleus is the defining property of an element and is related to the atomic number of the element.All atoms with same atomic number are atoms of same element.
Learn more about element,here:
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Answer and explanation;
-Phosphorous can be prepared from calcium phosphate by the following reaction: 2Ca3(PO4)2 + 6SiO2 + 10C -----> 6CaSi03 + P4 + 10CO
Phosphorite is a mineral that contains Ca3(PO4)2 plus other non phosphorous containing compounds.
-If the phosphorite sample is 75% Ca3(PO4)2 by mass, then;
mass of Ca3(PO4)2 is given by; 0.75 * (1000 g) = 750g
MM Ca3(PO4)2 = 310.19 g/mol
thus, Number of moles of Ca3(PO4)2;
= 750g / 310.19 g/mol
= 2.42 moles of Ca3(PO4)2 From the equation;
(2 mol Ca3(PO4)2 = 1 mol P4) Thus; moles of P4 will be;
=2.42 mol Ca3(PO4)2 * (1 mol P4 / 2 mol Ca3(PO4)2)
= 1.21 moles of P4 Mass of P4 will be;
=1.21 mol P4 * ( 4 x 30.974) g/mol
= 1.21 mol P4 * 123.896 g/mol
= 150 g P4. (2 sf)
Hence;
1.5 x10^(2) g P4 are produced from 1.0 kg Phosphorite mineral containing 75% Ca3(PO4)2.