Answer:
Copper turns green on exposure to air
Explanation:
Liquid water freezes to form ice: Physical change
Reason: Water can melt back when it becomes ice.
Copper turns green on exposure to air: Chemical change
Reason: The copper can not change back from the green state when it turns green.
My educated guess should be the 3rd one
Answer:
The pair co,Ni is out of order in terms of atomic mass
Explanation:
For co,Ni
Atomic mass of Co = 58.9331 u
Atomic mass of Ni = 58.6934
For Li,be
Atomic mass of Li = 6.941 u
Atomic mass of be = 9.012182 u
For I,xe
Atomic mass of I = 126.90447 u
Atomic mass of Xe = 131.293 u
Hence, the pair co,Ni is out of order in terms of atomic mass
Answer:
2 moles
Explanation:
The following were obtained from the question:
Molarity = 0.25 M
Volume = 8L
Mole =?
Molarity is simply defined as the mole of solute per unit litre of solution. It is represented mathematically as:
Molarity = mole of solute/Volume of solution.
With the above equation, we can easily find the number of mole of MgCl2 present in 8 L of 0.25 M MgCl2 solution as follow:
Molarity = mole of solute/Volume of solution.
0.25 = mole of MgCl2 /8
Cross multiply to express in linear form
Mole of MgCl2 = 0.25 x 8
Mole of MgCl2 = 2 moles
Therefore, 2 moles of MgCl2 are present in 8 L of 0.25 M MgCl2 solution
