During summer, the Earth's orbit brings Australia closer to the sun (as compared to Europe during its summer), resulting in an additional 7% solar UV intensity. Coupled with our clearer atmospheric conditions, this means that Australians are exposed to up to 15% more UV than Europeans.
Answer and explanation:
The attached figure shows five different structures for the chemical formula C4H5O5, but only one of these structures represent the malic acid.
Malic acid is a dicarboxylic acid, this means malic acid has two
-COOH groups. Also, malic acid is a secundary alcohol, which means it has a R2-C-OH group.
-Structure A has two carboxylic groups, but it doesn´t have a secundary alcohol.
-Structure B doesn´t have any caborxylic group.
-Structure C has two carboxylic groups and it is a secundary alcohol. Structure C is the Malic acid
Answer:
The mass percentage of the solution is 10.46%.
The molality of the solution is 2.5403 mol/kg.
Explanation:
A bottle of wine contains 12.9% ethanol by volume.
This means that in 100 mL of solution 12.9 L of alcohol is present.
Volume of alcohol = v = 12.9 L
Mass of the ethanol = m
Density of the ethanol ,d= 


Mass of water = M
Volume of water ,V= 100 mL - 12.9 mL = 87.1 mL
Density of water = D=1.00 g/mL

Mass percent


Molality :

M = 87.1 g = 0.0871 kg (1 kg =1000 g)


Answer:
D. all of these are chemical changes