Answer: a. two substances present; two phases present : Heterogeneous mixture
b. two substances present; one phase present
: Homogeneous mixture
c. one substance present; one phase present
: pure substance.
d. one substance present; two phases present: Heterogeneous mixture
Explanation:
A pure substance is a substance which contains definite composition of only one type of component. Hence, it cannot be separated by physical means.
Mixture is a substance which contains two or more than two types of components and they can be separated by physical means as well.
Homogeneous mixtures: It is a mixture that has uniform composition throughout the solution and the particle size or shapes are not different. There is no physical boundary between the dispersed phase and dispersion medium.
Heterogeneous mixtures: It is a mixture that has non-uniform composition throughout the solution and the particle size or shapes are also different. There is a physical boundary between the dispersed phase and dispersion medium.
Covalent
bonds = sharing of electrons between two atoms of the same elements or elements
close to each other on the periodic table. Usually they are metals sometimes
non-metals. In polar bonds electrons are
shared unequally. Non polar bonds share electrons equally.
Answer:
Draw circles to represent the electron shell of each atom overlapping the circles where the atoms are bonded. Add dots to represent the outer electrons of one type of atom (H). Add crosses to represent the outer electrons of the other type of atom (Cl). Make sure the electrons are always in pairs.
Explanation:
In chemistry, a mole is the base unit of the amount of substance in a system containing elementary entities (atoms, molecules, ions, electrons), and one mole of substance corresponds to the Avogadro's constant or 
entities. The stoichiometry equation that relates the amount of substance into the measurement in moles is
,
where 
is the number of moles, 
is the amount of substance and 
is the Avogadro's constant.
Therefore,
.
<span>There is an organic molecule. This means that it is made up of carbon and hydrogen atoms and forms the building blocks of the molecules within living creatures and organisms. This molecule is a hydrocarbon and is made completely out of carbon and hydrogen atoms.</span>
