m = mass of the block of iron = 25 g
Q = heat absorbed by the block of iron = 1200 J
ΔT = increase in the temperature of iron due to heat absorbed = ?
c = specific heat of block of iron = 0.450 J/(g C)
Heat absorbed by the block of iron is given as
Q = m c ΔT
inserting the values in the above formula
1200 = 25 (0.450) ΔT
1200 = (11.25) ΔT
ΔT = 1200/11.25
ΔT = 106.67 C
B. An electronegativity difference of greater than 2.7 between the atoms
C. An electronegativity difference of less than 1.7 between the atoms
D. An electronegativity difference of less than 2.7 between the atoms
Answer is: A. An electronegativity difference of greater than 1.7 between the atoms.
Electronegativity (χ) is a chemical property that describes the tendency of an atom to attract a shared pair of electrons towards itself.
Atoms with higher electronegativity attracts more electrons towards it, electrons are closer to that atom.
For example, in ionic salt sodium fluoride (NaF), fluorine has electronegativity approximately χ = 4 and sodium χ = 1 (Δχ = 4 - 1; Δχ = 3), fluorine attracts electron and it has negative charge and sodium has positive charge.
Answer : Gaseous water molecules condense when they cooled. Liquid water molecules evaporate when they heated.
Explanation :
Condensation : It is a process in which a phase changes from gaseous state to liquid state. This process occurs when the water molecules in the air cool down and they join together to form liquid water.
Evaporation : It is a process in which a phase changes from liquid state to gaseous state. This process occurs when the water is heated, the molecules in the water move and vibrate quickly that they escape into the atmosphere as water vapor.