An exergonic reaction proceeds with net release of free energy.
An endergonic reaction absorbs free energy
The initial temperature is 137.34 °C.
<u>Explanation:</u>
As the specific heat formula says that the heat energy required is directly proportional to the mass and change in temperature of the system.
Q = mcΔT
So, here the mass m is given as 23 kg, the specific heat of steel is given as c = 490 J/kg°C and the initial temperature is required to find with the final temperature being 140 °C. Also the heat energy required is 30,000 J.
ΔT =
ΔT =
Since the difference in temperature is 2.66, then the initial temperature will be
Final temperature - Initial temperature = Change in temperature
140-Initial temperature = 2.66
Initial temperature = 140-2.66 = 137.34 °C
Thus, the initial temperature is 137.34 °C.
The volume of the textbook calculated by the student written to 3 significant figures is 992cm³
- According to this question, a student calculates the volume of his textbook and arrived at an answer of 991.880 cm³.
- To round up this digit to 3 significant figures, which means that only 3 significant numbers should appear in the answer.
- To do this, the number after the third number is 8, which means we can round up the value of 1 to 2. Hence, the volume of the textbook calculated by the student is 992cm³ in 3 s.f.
Learn more at: brainly.com/question/16563962?referrer=searchResults
Answer:
Colors of transition metal compounds are due to two types of electronic transitions. Due to the presence of unpaired d electrons, transition metals can form paramagnetic compounds. Transition metals are conductors of electricity, possess high density and high melting and boiling points.
Explanation:
-20.16 KJ of heat are released by the reaction of 25.0 g of Na2O2.
Explanation:
Given:
mass of Na2O2 = 25 grams
atomic mass of Na2O2 = 78 gram/mole
number of mole = 
= 
=0. 32 moles
The balanced equation for the reaction:
2 Na2O2(s) + 2 H2O(l) → 4 NaOH(aq) + O2(g) ∆Hο = −126 kJ
It can be seen that 126 KJ of energy is released when 2 moles of Na2O2 undergoes reaction.
similarly 0.3 moles of Na2O2 on reaction would give:
= 
x = 
= -20.16 KJ
Thus, - 20.16 KJ of energy will be released.