Answer : The molal freezing point depression constant of liquid X is, 
Explanation : Given,
Mass of urea (solute) = 5.90 g
Mass of liquid X (solvent) = 450 g = 0.450 kg
Molar mass of urea = 60 g/mole
Formula used :
where,
= change in freezing point
= freezing point of solution = 
= freezing point of liquid X = 
i = Van't Hoff factor = 1 (for non-electrolyte)
= Molal-freezing-point-depression constant = ?
m = molality
Now put all the given values in this formula, we get
Therefore, the molal freezing point depression constant of liquid X is,
Answer:
5) Plant; 6) Heat; 7) never heard of chemosynthesis, sorry :(
Explanation:
A plant is the only thing in an ecosystem that uses photosyenthesis. This includes trees, algea, and grass.
80% of energy is lost as heat used in order to keep the animal warm.
I am really sorry I couldn’t help with 7!
To take the percent by mass of this element, we use the
formula:
% mass = (mass of element / mass of ore) * 100%
% mass = (47.5 g / (660 kg * 1000 g / kg)) * 100*
<span>% mass = 7.20 x 10^-3 %</span>
They have same chemical properties
for example the elements of group VIII are called noble gases .They are unreactive, odorless and colorless.
http://century.rochester.k12.mn.us/cms/One.aspx?portalId=3086882&pageId=6133921
Hope this helps!
Please mark brainliest. :)
