Answer:
c. crystallization
Explanation:
The opposing process that occur in a solution in contact with undissolved solute are dissolution and crystallization.
In the dissolution process the solid substance coverts into liquid state and mixes with solution. Whereas in Crystallization the the chemical is converted from the liquid solution to solid crystal state.
Answer:
option A= Physical change
Explanation:
physical change:
" It is a change in which no new substance is formed"
Breaking of object like glass is the example of physical change because it is not change into another object. It effect the form of object but can not change the chemical composition.
Chemical changes:
" it is a change in which one substance is converted into new product through chemical reaction".
During the chemical changes the types and the number of atom remain same but their arrangement changed.
for example: burning of wood, baking of cake, digesting food, resting of iron etc.
Physical reaction:
" physical reaction occur during the molecular rearrangement. There is no chemical change occur"
In this type of changes no bonds are break to form new bonds, for example boiling point.
Chemical reaction:
" chemical reaction occur when molecules are chemically react with each others and bonds formation and breaking is also occur"
Answer:
+15.8°
Explanation:
The formula for the observed rotation (α) of an optically active sample is
α = [α]<em>lc
</em>
where
<em>l</em> = the cell path length in decimetres
<em>c</em> = the concentration in units of g/100 mL
[α] = the specific rotation in degrees
1. Convert the concentration to units of g/100 mL
2. Calculate the observed rotation
The plants without any fertiliser could be the control, to see what the change in the independent variable (fertiliser) does to the growth of the plant (dependant variable).
Hope that helps.
Zinc carbonate has the chemical formula : ZnCO3 and the equation for thermal decomposition is:
ZnCO3 .................> ZnO + CO2
1 mole of ZnCO3 produces one mole of ZnO
From the periodic table:
molar mass of zinc = 65.38 gm
molar mass of carbon = 12 gm
molar mass of oxygen = 16 gm
molar mass of ZnCO3 = 65.38 + 12 + 3(16) = 125.38 gm
molar mass of ZnO = 65.38 + 16 = 81.38 gm
125.38 gm of ZnCO3 produces 81.38 gm of ZnO, therefore:
mass of ZnO in 375 gm = (375 x 81.38) / 125.38 = 243.4 gm
Based on the above calculations, the correct answer is 243 grams
