Answer: (a) There are 0.428 moles present in 12 g of 
molecule.
(b) There are 2 moles present in 
particles of oxygen.
Explanation:
(a). The mass of nitrogen molecule is given as 12 g.
As the molar mass of is 28 g/mol so its number of moles are calculated as follows.
So, there are 0.428 moles present in 12 g of molecule.
(b). According to the mole concept, 1 mole of every substance contains 
atoms.
Therefore, moles present in particles are calculated as follows.
So, there are 2 moles present in particles of oxygen.
Explanation:
The given data is as follows.
, 
Work produced per kJ of heat extracted from hot reservoir = 0.45 kJ = Efficiency
If the device is Carnot cycle then its efficiency will be maximum and its value will be equal to ![[1 - (\frac{T_{c}}{T_{h}} )]](https://tex.z-dn.net/?f=%5B1%20-%20%28%5Cfrac%7BT_%7Bc%7D%7D%7BT_%7Bh%7D%7D%20%29%5D)
Using this relation we will calculate the efficiency as follows.
Efficiency =
= 
= 0.928
Hence, it means that this type of device is possible and the claim is also believable.
Answer:
we need 6.0 moles of zinc (Zn)
Explanation:
Step 1: Data given
Number of moles ZnO produced = 6.0 moles
Step 2: The balanced equation
2 Zn + O2 → 2 ZnO
For 2 moles Zinc we need 1 mol Oxygen to produce 2 moles Zinc oxide
Step 3: Calculate moles zinc
For 2 moles Zn we need 1 mol O2 to produce 2 moles ZnO
For 6.0 moles 2nO produced, we need 6.0 moles of zinc (Zn) and 3.0 moles of O2 to react.
Answer:
cell wall
Explanation:
plants are the only cells that have cell walls. no other type of organism have a cell wall
