Answer:
Negative sign says that release of heat.
Explanation:
The expression for the calculation of the heat released or absorbed of a process is shown below as:-
Where,
is the heat released or absorbed
m is the mass
C is the specific heat capacity
is the temperature change
Thus, given that:-
Mass = 25.2 g
Specific heat = 0.444 J/g°C
So,
Negative sign says that release of heat.
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Answer:
0.0222 mole of NaOH is needed to react with NH4F
Explanation:
NH4F + NaOH --> NaF + NH3 + H2O
Data given
Mass of NH4F =0.821g, Concentration of NaOH= 1M, volume of NaoH =25ml
But mole = (CV)/1000
given mole of NaoH = (1 * 25)/1000 = 0.025moles of NaOH used
Molar mass of NH4F = 37g/mol
mole of NH4F used 0.821 / 37 = 0.0222 mole NH4F
Determine the excess and limiting reactant,
NaOH is in excess
0.025 - 0.0222 = 0.0028 mole NaOH excess
0.0222 mole of NaOH is required to react with NH4F
Answer:
Option A is correct
Explanation:
Potential energy of acorn is due to its position i.e height and kinetic energy Is due to velocity or speed with which it is moving. When the acorn is at tree, its potential energy is maximum and kinetic energy is zero. While it starts moving downward, the height starts reducing and the speed increase. Thus potential energy reduces and kinetic energy increases.
But as it touches the ground, its kinetic energy becomes zero as speed is zero and potential energy also becomes zero as height is zero.
Thus, option A is correct