Answer: 0.028 grams
Explanation:
Depression in freezing point :
Formula used for lowering in freezing point is,
or,
where,
= change in freezing point
= freezing point constant (for benzene} =
m = molality
Putting in the values we get:
0.028 grams of DDT (solute) must be dissolved in 209.0 grams of benzene to reduce the freezing point by 0.400°C.
Answer:
B. To change from a liquid state to a solid state is called Freezing
Answer:
669.48 kJ
Explanation:
According to the question, we are required to determine the heat change involved.
We know that, heat change is given by the formula;
Heat change = Mass × change in temperature × Specific heat
In this case;
Change in temperature = Final temp - initial temp
= 99.7°C - 20°C
= 79.7° C
Mass of water is 2000 g ( 2000 mL × 1 g/mL)
Specific heat of water is 4.2 J/g°C
Therefore;
Heat change = 2000 g × 79.7 °C × 4.2 J/g°C
= 669,480 joules
But, 1 kJ = 1000 J
Therefore, heat change is 669.48 kJ
It is an endothermic reaction because the products hAve more heat than the reactions so it was a gain of heat which makes the enthalpy Change positive !
This is covalent network type of solid.
For example, silicon dioxide (SiO₂) is covalent network solid with covalent bonding.
Covalent network solid is a chemical compound (or element) in which the atoms are bonded by covalent bonds in a continuous network extending throughout the material.
Silicon(IV) oxide has continuous three-dimensional network of SiO₂ units and diamond has sp3 hybridization.
This solids do not have free electrons so they are good insulators.
They have strong covalent bonds, so they melt at extremely high temperature.
Other examples are quartz, diamond, and silicon carbide.
More about network solid: brainly.com/question/15548648
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