Answer:
the the answer iss ( true )
Water is the answer because the word <span>Hydroelectric has hydro in it and hydro= water.</span>
The grams of Na that are needed to complete to react with 40..0 g of O2 is calculated as below
find the moles of O2 used = mass/molar mass
= 40 g/32g/mol = 1.25 moles
write the reacting equation
4Na+ O2 = 2Na2O
by use of mole ratio between Na to O2 which is 4 :1
the moles of Na = 1.25 x 4 = 5 moles
mass of Na = mass x molar mass
= 5 moles x 23 g /mol= 115 moles
Answer:
3.38 moles.
Explanation:
The following data were obtained from the question:
Mass of copper (Cu) = 215 g
Number of mole of copper (Cu) =...?
The number of mole of copper (Cu) in 215 g can be obtained as follow:
Mass of copper (Cu) = 215 g
Molar mass of copper (Cu) = 63.55 g/mol
Number of mole of copper (Cu) =...?
Mole = mass /Molar mass
Mole of Cu = 215/63.55
Mole of Cu = 3.38 moles
Therefore, 3.38 moles of copper (Cu) is present in the sample.
The common way the scientific knowledge is discovered passes through several steps:
First you observe the phenomenon around you. Then you develop a certain hypothesis based on your observation. After that you start testing your hypothesis and collecting the resultant data from your tests.
Finally comes the conclusion of whether your hypothesis is accepted or rejected.
If it is accepted, it can further develop into a theory and a publication afterwards.
The answer is: hypothesis
