Answer:
247 ml
Explanation:
How many mL of 0.150 M HF solution are required to produce 0.0370 moles of HF 0.150 moles/ liter = 0.150/1000 moles/ml =0.000150 moles/ml
0.000150 x ? = 0.0370 moles HF
? = 0.0370/0.000150 = 247 ml
check
247 ml = 247/1000 L = 0.247
(0.247) x (0.150) =0.370 check
Since there are no given items, I will give a general answer. Energy....or the lack of it. Examples: Heat, electricity, force (when an item is moving and it impacts something, it heats up...friction is an example of this), etc
Answer:
Paper Chromatography
Explanation:
Most leaves are green due to chlorophyll pigments of different types like chlorophyll A, chlorophyll B, etc. All these pigments will be seperated according to their molecular composition. So, the correct option is 'Paper Chromatography'.
Answer:
Effective nuclear charge and ionization energy decreased down in the column.
Explanation:
Along Group:
As we move from top to bottom in group the atomic size increases with increase of atomic number. The electron is added into the next shell hence the valance electrons farther away from the nucleus and hold of nucleus become weaker on the valance electrons. The addition of electrons also increase the shielding and protect the outer electrons from the hold of nucleus. Thus it becomes easier to remove the electron from an atom and less energy is required that's why ionization energy decreases from top to bottom and effective nuclear charge also decrease because of shielding effect.
Along period:
As we move from left to right across the periodic table the number of valance electrons in an atom increase. The atomic size tend to decrease in same period of periodic table because the electrons are added with in the same shell. When the electron are added, at the same time protons are also added in the nucleus. The positive charge is going to increase and this charge is greater in effect than the charge of electrons and shielding remain constant due to addition of electron in same shell. This effect lead to the greater nuclear attraction. The electrons are pull towards the nucleus and valance shell get closer to the nucleus. As a result of this greater nuclear attraction atomic radius decreases and ionization energy increases.
