When electrons absorb energy they are able to move from their ground states up to excited states. The answer is letter B. an example of this is when you light a match. The molecules of the matchstick are in its ground state. When you flick it on the ground or anything hard, it causes its molecules to move into the excited state and thus causing fire.
Answer:
Melting point of aqueous solution = -10.32 °C
Explanation:
Where,
ΔT_f = Depression in freezing point
k_f = molal depression constant
m = molality
Formula for the calculation of molality is as follows:
density of water = 1 g/mL
density = mass/volume
Therefore,
mass = density × volume
volume = 3 L = 3000 mL
Mass of water = 1 g/mL × 3000 mL
= 3000 g
van't Hoff factor (i) for MgCl2 = 3
Substitute the values in the equation (1) to calculate depression in freezing point as follows:
Melting point of aqueous solution = 0 °C - 10.32 °C
= -10.32 °C
Answer:
The melting point of the solution is - 1.953 °C
Explanation:
In an ideal solution, the freezing point depression is computed as follows:
where:
is the freezing-point depression
is the cryoscopic constant, in this case is equal to 1.86
b is the molality of the solution
i is the van't Hoff factor, number of ion particles per individual molecule of solute, in this case is equal to 3
Molality is defined as follows:
b = moles of solute/kg of solvent
Moles of solute is calculated as follows:
moles of solute = mass of solute/molecular weight of solute
In this case there are 100 g of solute and its molecular weight is 35.5*2 + 24 = 95 g/mole. So, the moles are:
moles of solute = 100 g/(95 g/mol) = 1.05 moles
The mass of solvent is computed as follows:
mass of solvent = density of solvent * Volume of solvent
Replacing with the data of the problem we get:
mass of solvent = 1 kg/L*3 L = 3 kg
Finally, the molality of the solution is:
b = 1.05/3 = 0.35 mol/kg
Then, the freezing-point depression is:
The freezing-point depression is the difference between the melting point of the pure solvent (here water) and the melting point of the solution. We know that the the melting point of water is 0 °C, then:
melting point of water - melting point of the solution = 1.953 °C
melting point of the solution = 0 °C - 1.953 °C = - 1.953 °C
Describe how the catalyst, zymase speeds up the reaction shown
The catalyst zymase speeds up the reaction by catalyzing the fermentation of sugar into ethanol and carbon dioxide. It is mostly present in yeasts.
True
False
Answer:
It should be used 2 digits to the right of the decimal point to report the result
Explanation:
When adding or subtracting two decimal numbers, the number of digits to the right of the decimal point in the result is equal to the amount with the least number of decimal places.
In this case we have 4 decimal places in 0.0136 g, 2 decimal places in 2.70 × 10-4 g and 2 decimal places in 4.21 × 10-3 g, so, the least number of decimal places is 2 and that should be the number of digits to the right of the decimal point in the result.
Then the result of the sum should be 9.66 × 10-3 g
I got 2.......................