Answer:
Heat required to melt 26.0 g of ice at its melting point is 8.66 kJ.
Explanation:
Number of moles of water in 26 g of water: 26× 
moles
=1.44 moles
The enthalpy change for melting ice is called the entlaphy of fusion. Its value is 6.02 kj/mol.
we have relation as:
q = n × ΔH
where:
q = heat
n = moles
Δ
H = enthalpy
So calculating we get,
q= 1.44*6.02 kJ
q= 8.66 kJ
We require 8.66 kJ of energy to melt 26g of ice.
B-The body could break down proteins from muscles for energy.
<span>4FeS2 + 11O2 = 2Fe2O3 + 8SO2</span>
Percent yield is calculated as the actual yield divided by the theoretical yield multiplied by 100.
Actual yield = 55 g ( 1 mol / 159.69 g ) = 0.34 mol Fe2O3
To find for the theoretical yield, we first determine the limiting reactant.
100 g O2 ( 1 mol / 32 g) = 3.13 mol O2
200 g FeS2 (1 mol / 119.98g) = 1.67 mol FeS2
Therefore, the limiting reactant is O2.
Theoretical yield = 3.13 mol O2 ( 2 mol Fe2O3 / 11 mol O2 ) = 0.57 mol Fe2O3
Percent yield = (0.34 mol / 0.57 mol) x 100 = 59.74%
O is what should go in the blank. O stands for Oxygen.
Answer:
Because only a few bacterias can "fix" the atmosphere nitrogen.
Explanation:
The nitrogen at the atmosphere is in the form of N₂ and represents 78% of the atmosphere composition. The element is part of the constitution of nucleic acids and proteins, so the living beings needed them.
However, the animals and the plants can't catch the N₂. Some bacterias that live in mutualism with plants have this ability, and they "fix" the atmosphere nitrogen, transforming the N₂ in the ions nitrite (NO₃⁻) or ammonia (NH₃), which can be caught by the plants.
Them, when the primary consumers eat the plants they catch the nitrogen, which will be passed through the food chain.
So, it's difficult to pull nitrogen from the atmosphere into the nitrogen cycle of the biosphere because only a few bacterias can do it.
