Answer:
Average of measurements = 20.97 cm
Explanation:
Given data:
Three measurements of pete's = 20.9 cm, 21.0 cm, 21.0 cm.
Average value of measurements = ?
Formula:
Average of measurements = sum of all measurements / Total number of measurements
Solution:
Average of measurements = 20.9 cm + 21.0 cm + 21.0 cm. / 3
Average of measurements = 62.9 cm / 3
Average of measurements = 20.97 cm
Answer:
4,1,5,3,2 (from left to right)
Answer:
138.96kJ is the maximum electrical work
Explanation:
The maximum electrical work that can be obtained from a cell is obtained from the equation:
W = -nFE
<em>Where W is work in Joules,</em>
<em>n are moles of electrons = 2mol e- because half-reaction of Zn is:</em>
Zn(s) → Zn²⁺(aq) + 2e⁻
F is faraday constant = 96500Coulombs/mol
E is cell potential = 0.72V
Replacing:
W = -2mol*96500Coulombs/mol*0.72V
W = - 138960J =
<h3>138.96kJ is the maximum electrical work</h3>
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Answer:
The physical and chemical properties of the product do not match the properties of the reactant.
Explanation:
Chemical change:
The changes, that occur due to change in the composition of a substance and result in a different compound is known as chemical change.
These changes are irreversible
These changes occur due to chemical reactions
These may not be observed with naked eye
Example:
Combustion of fuel or wood: that oil or wood convert into energy, CO2 and ash in case of wood
Boiling of egg: that change the chemical composition of protein in the egg .
The reaction of Hydrogen and oxygen:
H 2 (g) + O 2 (g) -------------------------------------> 2H 2O (l)
The reaction between sugar and oxygen form a product which is different from the reactant that's why it indicate the occurrence of chemical reaction.
While in case of physical changes just state of matter are changed. Properties remain same.
Answer:
The total amount of heat released is 68.7 kJ
Explanation:
Given that:
mass of water = 94.0 g
moles of water = 94 / 18.02 = 5.216
80⁰C ------> 0⁰C --------> -30⁰C
Q1 = m Cp dT
= 94 x 4.184 x (0 - 80)
= -31463.68 J
= -31.43 kJ
Q2 = 6.01 x 10^3 x 5.216
= - 31348.16 J
= -31.35 kJ
Q3 = - 94 x 2.09 x 30
= - 5893.8 J
= -5.894 kJ
Total heat = Q1 + Q2 + Q3 = -31.43 kJ + (-31.35 kJ ) + (-5.894 kJ
) = -68.7 kJ
Total heat released = -68.7 kJ
Note that the "negative sign" simply indicates heat released, therefore no need to put it in the answer.
