The similarities of physical and chemical changes is that both of those changes change the way the object looks by it's physical appearance. Also they use a type of element to change that object.
Answer:
b. milk spoiling and c. firecrackers exploding
Explanation:
These are both chemical changes, the composition of them change when this happens and it cannot be reversed
Answer:
1.12g/mol
Explanation:
The freezing point depression of a solvent for the addition of a solute follows the equation:
ΔT = Kf*m*i
<em>Where ΔT is change in temperature (Benzonitrile freezing point: -12.82°C; Freezing point solution: 13.4°C)</em>
<em>ΔT = 13.4°C - (-12.82) = 26.22°C</em>
<em>m is molality of the solution</em>
<em>Kf is freezing point depression constant of benzonitrile (5.35°Ckgmol⁻¹)</em>
<em>And i is Van't Hoff factor (1 for all solutes in benzonitrile)</em>
Replacing:
26.22°C = 5.35°Ckgmol⁻¹*m*1
4.90mol/kg = molality of the compound X
As the mass of the solvent is 100g = 0.100kg:
4.9mol/kg * 0.100kg = 0.490moles
There are 0.490 moles of X in 551mg = 0.551g, the molar mass (Ratio of grams and moles) is:
0.551g / 0.490mol
= 1.12g/mol
<em>This result has no sense but is the result by using the freezing point of the solution = 13.4°C. Has more sense a value of -13.4°C.</em>
They all have the same number of electrons in the electron cloud.
A molecule that has a central atom surrounded by three single bond pairs and one unshared pair would have a trigonal pyramidal shape. The electon arrangement of this is called tetrahedral. It involves one atom located at the apex and at the corners are three atoms with a trigonal base. An example would be ammonia or NH3. Nitrogen has five valence electrons so that it needs to three more electrons to satisfy the octet rule and be stable. It would share electrons with the three nitrogen present. In order, to achieve the most stable geometry, the three atoms of hydrogen would attach with a bond angle of 109 degrees.
