Answer:
For a hypothesis to be testable means that is it possible to make observations that agree or disagree with it. This statement may or may not be true, but it is not a scientific hypothesis. That's because it can't be tested.
Explanation:
As aluminium loses 12 moles of electrons oxygen gain 12 moles of electrons.
Explanation
4Al + 3 O2→ Al2O3
first write the ions of Aluminium and oxygen
that is, Aluminium ion is = Al^3+
oxygen ion is = O^2-
therefore one atom of Al loses 3 electrons moles while
one atom of O gain 2 electrons moles
from equation above there a total of number of Al atom are 4 =( 1 x4=4) atoms while
Oxygen atoms are 6= ( 3 x2=6) atoms
therefore the total number of Moles of Al lost is = 3 x 4 = 12 moles of electrons
total number of moles of O gained = 2 x6 = 12 moles of electrons
Answer:
B. Prokaryotes do NOT have a nucleus.
Answer: pure substances.
Explanation:
The given substances are:
All what surrounds us, which has mass and occupies spaces, is matter. There are two kind of matter: pure substances and mixtures.
Pure substances have a uniform and constant composition. On the other hand, mixtures are combinations of two or more pure substances in any arbitratry ratio.
Pure substances may be elements or compounds. The elements are the substances conmposed by one only kind of atom. In the list of substances given, Li and O₂ are elements: all the atoms in Li are lithium, and all the atoms in O₂ are oxygen atoms.
Compounds are the chemical combination of two or more different kind of atoms. In the given list H₂O₂ and NaCl are compounds. As you see, H₂O₂ contains atoms of hydrogen and oxygen, chemically bonded, in a fixed ratio (2 atoms of hydrogen by 2 atoms of oxygen). And NaCl has atoms of Na (sodium) and Cl (chlorine), chemicaly bonded, in a fixed ratio (1:1).
There are only 118 known elements and you can find them in any modern periodic table. Therer are virtually infinitely many compounds since many different combinations of the elements can be attained.
Elements and compounds have in common that they are classified as pure substances.
Ionic bonds form when a nonmetal and a metal exchange electrons, while covalent bonds form when electrons are shared between two nonmetals. An ionic bond is a type of chemical bond formed through an electrostatic attraction between two oppositely charged ions.
