Answer:
15000N/m²
Explanation:
Given parameters:
Force exerted by the girl = 450N
Area = 300cm²
Unknown:
Pressure exerted by her feet =?
Solution:
Pressure is the force per unit area on a body;
Pressure = 
We need to convert the given area to m²;
10000cm² = 1m²
300cm² = 
= 0.03m²
Pressure = 
= 15000N/m²
19.927 moles are in 1.20 times 
atoms of phosphorus.
<h3>What are moles?</h3>
A mole is defined as 6.02214076 ×
of some chemical unit, be it atoms, molecules, ions, or others.
1 mole of any substance contain Avogadro's number of molecules so we can calculate the number of moles by dividing the provided number of atoms over Avogadro's number to obtain the number of moles .
Moles= 
Moles= 1.20 X atoms ÷ 6.022 X
= 19.927
Hence, 19.927 moles are in 1.20 times atoms of phosphorus.
Learn more about moles here:
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Answer:
Whether you get the metal or hydrogen during electrolysis depends on the position of the metal in the reactivity series: the metal will be produced if it is less reactive than hydrogen. hydrogen will be produced if the metal is more reactive than hydrogen.
Explanation:
Physical changes only change the appearance of a substance, not its chemical composition.
Chemical changes cause a substance to change into an entirely substance with a new chemical formula.
Chemical changes are also known as chemical reactions. The “ingredients” of a reaction are called reactants, and the end results are called products
A synthesis would be A+B-->AB its combining, decomposition is AB-->A+B, its the breaking up of a substance.
