See the correct answer is b.)PbS
Answer:
Both <u>elements </u>and <u>compounds</u> can be classifies as pure substances because they have distinct properties and composition.
Explanation:
Elements and compounds are considered as pure substances because both are always formed form are have same kind of atoms.
For example,
Carbon dioxide is compound. It always consist of one carbon atom and two oxygen atoms.
Water is compound it always have same kind of atoms two hydrogen and one oxygen that's why compounds are considered as pure substances.
Same is the case with elements. For example,
Hydrogen is element and it always consist of H atoms.
Iron is another element and it always have iron atoms.
So elements and compounds are always consist of same substances that's why they are considered as pure.
Answer:
B-Sucrose molecules are too large to conduct electricity in once dissolved in water.
D-Salts, like NaCL, have ionic bonds and are considered to be electrolytes:when dissolved in water, salts dissociate and form ions.
Explanation:
The first law states that the total increase in the energy of a system is equal to the increase in thermal energy, meaning that heat is a form of energy and is therefore subject to the the principle of conservation
