The symbol %v/v means percent by volume. Assuming there is no volume effects when these substances are mixed, we calculate as follows:
% v/v = (25 mL ethanol / 25 mL + 150 mL ) x 100
%v/v = 14.29 mL ethanol / mL solution
Hope this answers the question.
Answer:
(1) atomic numbers
Explanation:
The observed regularities in the properties of the elements on the periodic table are periodic functions of their atomic numbers.
- Atomic number is the number of protons in an atom.
- The periodic law states that "the properties of elements are a periodic function of their atomic number".
- Elements on the periodic table are arranged based on the atomic numbers they contain.
- The number of positively charged particles in an atom is the atomic number.
The three of them have the same amount of electrons, so we can’t determine the right one on that ground. As you might know, Pauli said that electrons are always in the position of the lowest energy. So the first situation is impossible because there is a free place available that takes less energy. Then the 3rd situation is nor possible because if one electron has a different spin than the others, there is a magnetic obstruction that be prevented if the spin changes. This means that the second situation is the right one.
The heat of the reaction, in kJ, when 4.18 g of the hydrocarbon are combusted 775.70 kJ.
The heat energy is given as :
q = m c ΔT + Ccal ΔT
q = ( 974 g× 4.184 ×6.9) + 624 ×6.9
q = 32424.59 J
moles of hydrocarbon = 0.0418 mol
heat of combustion = 32424.59 J / 0.0418 mol
= 775707.89 J
= 775.70 kJ
Thus, A 4.18 g sample of a hydrocarbon is combusted in a bomb calorimeter that contains 974 g of water. the temperature of the water increases by 6.9 °C when the hydrocarbon is combusted. the calorimeter constant for the calorimeter was determined to be 624 J/°C. what is the heat of the reaction is 775.70 kJ.
To learn more about calorimeter here
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The number of grams of NaOH that are needed to make 500 ml of 2.5 M NaOH solution
calculate the number of moles =molarity x volume/1000
= 2.5 x 500/1000 = 1.25 moles
mass = moles x molar mass of NaOH
= 1.25 x40= 50 grams of NaOH
