Answer:
<em>O</em><em>r</em><em>g</em><em>a</em><em>n</em><em>i</em><em>s</em><em>m</em><em> </em><em>,</em><em> </em><em>P</em><em>o</em><em>p</em><em>u</em><em>l</em><em>a</em><em>t</em><em>i</em><em>o</em><em>n</em><em> </em><em>,</em><em> </em><em>C</em><em>o</em><em>m</em><em>m</em><em>u</em><em>n</em><em>i</em><em>t</em><em>y</em><em> </em><em>,</em><em> </em><em>E</em><em>c</em><em>o</em><em>s</em><em>y</em><em>s</em><em>t</em><em>e</em><em>m</em><em> </em><em>.</em>
Explanation:
<u>Organism</u> is one type of species .
<u>Population</u> is a group of same species living together .
<u>Community</u> is a group of different species living together .
<u>Ecosystem</u> is a large group of community of species and its environment consisting of biotic and abiotic factor .
Answer:
The two valid principles are:
- Scientific theories can be replaced by better theories.
- An experiment can disprove a theory that scientists have accepted.
Explanation:
The scientific knwoledge is not inmutable; it may (and does) change with new discoveries.
In fact, scientific theories cannot be proved right, instead they are constantly tested to try to disprove them. This is what the principle that theories are falsiable means.
As long as a scientific theory is not disproved it remains valid, but new discoveries may lead, eventually, to its disprovement.
Scientific knowledge evolves because new procedures, new technologies, and new evidence leads to a better understanding and better explanations.
Answer:
6.4 × 10^-10 M
Explanation:
The molar solubility of the ions in a compound can be calculated from the Ksp (solubility constant).
CaF2 will dissociate as follows:
CaF2 ⇌Ca2+ + 2F-
1 mole of Calcium ion (x)
2 moles of fluorine ion (2x)
NaF will also dissociate as follows:
NaF ⇌ Na+ + F-
Where Na+ = 0.25M
F- = 0.25M
The total concentration of fluoride ion in the solution is (2x + 0.25M), however, due to common ion effect i.e. 2x<0.25, 2x can be neglected. This means that concentration of fluoride ion will be 0.25M
Ksp = {Ca2+}{F-}^2
Ksp = {x}{0.25}^2
4.0 × 10^-11 = 0.25^2 × x
4.0 × 10^-11 = 0.0625x
x = 4.0 × 10^-11 ÷ 6.25 × 10^-2
x = 4/6.25 × 10^ (-11+2)
x = 0.64 × 10^-9
x = 6.4 × 10^-10
Therefore, the molar solubility of CaF2 in NaF solution is 6.4 × 10^-10M
If it is blue litmus paper, it will remain blue. If it is red litmus paper, it will remain red. Water is neither an acid nor a base so it will not change the litmus paper.
