Answer:
The Answer is B. X: Opaque Objects
> > > Y: Transparent Objects
Explanation:
Answer:
207.24.
Explanation:
The mass numbers of the 4 isotopes are 82+ 122 = 204, 82 + 125 = 207,
82 + 124 = 206 and 208.
The approximate atomic mass is worked out by adding the products of their relative abundances and mass numbers:
0.014*204 + 0.221*207 + 0.241*206 + 0.524*208
= 207.24.
Answer:
[∝] = +472
Explanation:
Specific rotation in a solution is defined as:
[∝] = ∝ / c×l
Where:
[∝] is specific rotation, ∝ is observed rotation (In degrees), c is concentration in g/mL and l is path length (In dm).
∝: +47.2°
c: 2.0g / 50mL = 0.04g/mL
l: 25cm × (1dm /10cm) = 2.5dm
Replacing:
[∝] = +47.2° / 0.04g/mL×2.5dm = <em>+472</em>
I hope it helps!
Forests and prairies are examples of ecosystems on land. An ecosystem is a community of living things. Members survive by interacting with each other and with their environment. At first glance, the ocean seems like one big ecosystem.
-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.
