Answer:
not sure
Explanation:
a physical change (can)change.,....
Answer:
OPTION (A) : Testing a rock sample for gold content
Explanation:
For testing a rock sample of gold content you will need a Chemist. To test the material, the sample is rubbed on black stone which will leave a mark on the stone. This mark is tested by applying aqua fortis i.e nitric acid on the mark. If the mark gets dissolve then the material is not gold. If the mark sustain the it is further tested by applying aqua regia i.e nitric acid and hydrochloric acid which will prove the sample is of gold if it gets dissolve on using hydrochloric acid. The purity of the sample can be checked by differing the concentration of the aqua regia and comparing it with the gold material of the known purity.
Answer:
Increasing atomic number - True
Explanation:
The modern table is based on Mendeleev’s table, except the modern table arranges the elements by increasing atomic number instead of atomic mass.
The Atomic number is the number of protons in an atom, and this number is unique for each element. For example, Hydrogen has an atomic number of 1, Calcium has an atomic number of 20.
In the modern periodic table the elements are further arranged into:
- rows, called periods, in order of increasing atomic number. Elements in the same periods have the same number of shells.
- vertical columns, called groups, where the elements have similar properties. Elements in the same group has the same number of valency (outermost number of electrons)
Relative dating is the process of determining whether an object or event is older or younger than other objects or events. Absolute dating is d<span>etermining the age of an event or object in years. From absolute dating, the real age of the object is obtained which is not present for relative dating. Hope this helps.</span>
B)The concentration of the acid (C₁) is the same as that of the base (C₂).
V₁=V₂
n(acid)=C₁V₁
n(base)=C₂V₂
HX + YOH = YX + H₂O
n(acid)=n(base)
C₁V₁=C₂V₂
C₁=C₂
