Answer:
B. Ca(NO2)2
Explanation:
Ions (charged atoms) combine with one another to form stable ionic compounds. In this case, calicium ion (Ca2+) is said to react with NO2, which has a charge of -1 i.e. +1-1(2) = 1-2 = -1.
This means that calcium has a charge of +2 while nitrite ion has charge of -1, hence, when they combine, they exchange their charges, which become their subscript as follows:
Ca2+ + NO2- → Ca(NO2)2
Ca(NO2)2 is a stable ionic compound called calcium nitrite. Notice that it takes two atoms of NO2- to react with one atom of Ca2+.
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
Van der waals force
Explanation:
The intermoleclular forces are attraction between molecules. Interatomic forces are attraction between atoms in a compound.
In most hydrocarbons the weak Van der waals attraction are known.
- These forces are weak attraction joining non-polar and polar molecules together.
- These forces can also be found in layers of graphite.
- They are of two types;
London dispersion forces are attraction that exists between non-polar molecules and the noble gas.
Dipole - Dipole attractions are forces of attraction existing in polar molecules.
In hydrocarbons, we have non-polar molecules and intermolecular attraction is london dispersion forces.
learn more:
Intermolecular forces brainly.com/question/10107765
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