Answer:
9.94 mL, the volume of ethanol needed
Explanation:
The reaction is:
C₂H₅OH(l) + 3 O₂(g) → 2 CO₂(g) + 3 H₂O(l)
We convert the mass of the formed product to moles:
15 g . 1mol / 44g = 0.341 moles
2 moles of dioxide are produced by 1 mol of ethanol, in order to stoichiometry.
Therefore, 0.341 moles of CO₂ must be produced by (0.341. 1) / 2 = 0.1705 moles of alcohol.
We convert the moles to mass, and then, the mass to volume by the use of density.
0.1705 mol . 46 g / 1 mol = 7.84 g of ethanol
Ethanol density = Ethanol mass /Ethanol volume
Ethanol volume = Ethanol mass /Ethanol density → 7.84 g /0.789 g/mL =
9.94 mL
A molecule is defined as two or more atoms of the same element different element that are bound together. A molecule may be homonuclear, which means, it consists of atoms of one chemical element, as with oxygen (O2); or it may be heteronuclear, a chemical compound composed of more than one element, as with water (H2O).
88g ( so sorry if this isn’t correct )
Answer:
The wavelength of the line in the emission line spectrum of hydrogen caused by the transition of the electron for the given energy levels is 
Explanation:
Given :
The energy E of the electron in a hydrogen atom can be calculated from the Bohr formula:

= Rydberg energy
n = principal quantum number of the orbital
Energy of 11th orbit = 

Energy of 10th orbit = 

Energy difference between both the levels will corresponds to the energy of the wavelength of the line which can be calculated by using Planck's equation.


(Planck's' equation)


The wavelength of the line in the emission line spectrum of hydrogen caused by the transition of the electron for the given energy levels is 
Answer: Meniscus
Explanation: There is a condition on reading volumes. For concave meniscus read volume in the lower part and for convex meniscus read volume at the upper part.