Answer: 
will not occur.
Explanation:
A single replacement reaction is one in which a more reactive element displaces a less reactive element from its salt solution. Thus one element should be different from another element.
A general single displacement reaction can be represented as :
a)
Flourine is more reactive than chlorine and hence this reaction cannot occur.
b) 
Sodium is more reactive than zinc and hence the reaction will occur.
c) 
Iron is more reactive than copper and hence the reaction will occur.
d) 
Magnesium is more reactive than hydrogen and hence the reaction will occur.
Answer:
null
Explanation:
the hypothesis is a typical statistical theory which suggest that no statistical relationship and significance exists in a set of a given single observed variable between two sets of the observed data and measured phenomena
Answer:
Mass = 20 g
Explanation:
Given data:
Number of moles of He = 5 mol
Mass of He = ?
Solution:
Formula:
Number of moles = mass/ molar mass
Molar mass = 4 g/mol
by putting values,
5 mol = Mass / 4 g/mol
Mass = 5 mol × 4 g/mol
Mass = 20 g
.Thermal energy, an extensive property, depends on the number of particles in a substance as well as the amount of energy each particle has. If either the number of particles or the amount of energy in each particle changes, the thermal energy of the sample changes. With identi- cally sized samples, the warmer substance has the greater ther- mal energy. hope that helps.
