Electronegativity of an element decreases as we move down a group on the periodic table and electronegativity increases while moving from left to right across a period on the periodic table.
Explanation:
- The electronegativity increases as we move from left to right across a period because from left to right across a period, the nuclear charge is increasing Hence the attraction for the valence electrons also increases.
- As we move down a group, the atoms of each element have an increasing number of energy levels. The distance between the nucleus and valence electron shell increases and reduces the attraction for valence electrons. Hence electronegativity decreases as we move from top to bottom down a group.
<span>Energy = Mass * heat capacity * temperature change so,
</span>The energy added is 435 J and the temperature has to increase since the energy is added.
<span>435 J = 10.0 g * 0.89 J/gC * temperature change </span>
<span>Temperature change = 48.9 C </span>
<span>The initial temperature is 25.0 C, the final temperature is 25.0 C + 48.9 C = 73.9 C.</span>
Temperature is related to the kinetic energy the atoms within any given
substance. Within a solid, we can therefore assume that the density will
increase as the solid is cooled to a low temperature, as this will
cause a loss in kinetic energy and the atoms won't be able to move as
freely.
Answer:
10.5g
Explanation:
First, let us calculate the number of mole of NaHCO3 present in the solution. This is illustrated below:
Volume = 250mL = 250/1000 = 0.25L
Molarity = 0.5M
Mole =?
Molarity = mole /Volume
Mole = Molarity x Volume
Mole = 0.5 x 0.25
Mole = 0.125 mole
Now, we shall be converting 0.125 mole of NaHCO3 to grams to obtain the desired result. This can be achieved by doing the following:
Molar Mass of NaHCO3 = 23 + 1 + 12 +(16x3) = 23 + 1 +12 +48 = 84g/mol
Number of mole of NaHCO3 = 0.125 mole
Mass of NaHCO3 =?
Mass = number of mole x molar Mass
Mass of NaHCO3 = 0.125 x 84
Mass of NaHCO3 = 10.5g
Therefore, 10.5g of NaHCO3 is needed.
Answer:
1) polar
2)polar (not too sure about this one)
3)nonpolar
