Answer:
Rb: [Kr] 5s
Step-by-step explanation:
Rb is element 37, the first element in Period 5.
It has one valence electron, so its valence electron configuration is 5s.
The noble gas configuration uses the symbol of the previous noble gas as a shortcut for the electron configurations of the inner electrons.
The preceding noble gas is Kr, so the electron configuration is Rb: [Kr] 5s.
A. p block
from 3a-8a are in the p block including halogen
Balanced equation:
<span>2 NO + 5 H2 ------> 2 NH3 + 2 H2O
</span>
<span>2 moles NO react with 5 moles H2 to produce 2 moles NH3
</span>
<span>Molar mass of NO = 30.00 g/mol </span>
<span>86.3g NO = 86.3/30.00 = 2.877 moles of NO </span>
<span>This will require: 2.877*5 / 2 = 7.192 moles of H2 </span>
<span>Molar mass of H2 = 2 g/mol </span>
<span>25.6g H2 = 25.6/2 = 12.7 mol H2. </span>
<span>You have excess H2 means the NO is limiting </span>
<span>From the balanced equation: </span>
<span>2 moles of NO will produce 2 moles of NH3 </span>
<span>2.877 moles of NO will produce 2.877 moles of NH3 </span>
<span>Molar mass NH3 = 17g/mol </span>
<span>Mass NH3 produced = 2.877 * 17 = 48.91g
Hence the yield is = 48.91 g ~ 49 g</span>
Answer:
Chopping wood logs
A pot of water o a grate over a burning fire
Explanation:
Physical change is easily reversible. Burning/combustion is a chemical process where substances react rapidly with oxygen: this is usually irreversible.
The marshmallow, roasted food and burned wood all undergo combustion and hence are tagged chemical changes.
Explanation:
