1.51 x 10²⁵atoms
Explanation:
Given parameters:
Mass of Na = 578g
Unknown:
Number of atoms = ?
Solution:
To find the number of atoms, we must first find the number of moles the given mass contains.
Number of moles = 
molar mass of Na = 23g
Number of moles = 
= 25.13moles
1 mole of a substance = 6.02 x 10²³atoms
25.13 mole of Na = 25.13 x 6.02 x 10²³atoms
This gives 1.51 x 10²⁵atoms of Na
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Answer:
Lichens can be used as air pollution indicators, especially of the concentration of sulphur dioxide in the atmosphere. Lichens are organisms that grow in exposed places such as rocks or tree bark. They need to be very efficient at absorbing water and nutrients to grow there.
Answer:
the mixture or solution is called homogeneous mixture
Answer:
B. Ca2+ import into the ER because it has the steeper concentration gradient
Explanation:
ΔGt = RT㏑(C₂/C₁)
where ΔGt is the free energy change for transport; R = 8.315 J/mol; T = 298 K; C₂/C₁ is ratio of concentrations inside and outside each organelle.
For Ca²⁺ import
ΔGt = 8.315 J/mol * 298 K * ㏑(10⁻³/10⁻⁷)
ΔGt= 3.42 kJ/mol
For H⁺ import
ΔGt = 8.315 J/mol * 298 K * ㏑ (10⁻⁴/10⁻⁷)
ΔGt = 2.73 kJ/mol
From the above values, ΔGt is greater for Ca²⁺ import because it has a steeper concentration gradient
