The answer is chemical change
That is exploding of potassium metal when placed in water is chemical change.
When potassium is dropped into a beaker full of water then potassium moves about rapidly and then ignites within seconds, that is the metal is gone and all activity ceases.
So it an example of chemical change.
The reaction of potassium with water is as follows:
2K + 2H₂O ---->2KOH + H₂
This question can be simply solved by using heat formula,
Q = mCΔT
Q = heat energy (J)
m = Mass (kg)
C = Specific heat capacity (J / kg K)
ΔT = Temperature change (K)
when water freezes, it produces ice at 0°C (273 K)
hence the temperature change is 25 K (298 K - 273 K)
C for water is 4186 J / kg K or 4.186 J / g K
By applying the equation,
Q = 456 g x 4.186 J / g K x 25 K
= 47720.4 J
= 47.72 kJ
hence 47.72 kJ of heat energy should be removed.
19.927 moles are in 1.20 times atoms of phosphorus.
<h3>What are moles?</h3>
A mole is defined as 6.02214076 × of some chemical unit, be it atoms, molecules, ions, or others.
1 mole of any substance contain Avogadro's number of molecules so we can calculate the number of moles by dividing the provided number of atoms over Avogadro's number to obtain the number of moles .
Moles=
Moles= 1.20 X atoms ÷ 6.022 X
= 19.927
Hence, 19.927 moles are in 1.20 times atoms of phosphorus.
Learn more about moles here:
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Answer:
2.00 g of ethanol
Explanation:
The density of the mixture is the total mass (ethanol + chloroform) divided by the total volume. Let's call the mass of ethanol as x, the volume of it as V1, and the volume of chloroform as V2.
V2 = mass of chlorofrom/density
V2 = 5/1.5 = 3.33
x = density*volume
x = 0.8*V1
The density of the mixture will be:
(x + 5)/(V1 + V2) = 1.2
(0.8*V1 + 5)/(V1 + 5/1.5) = 1.2
0.8V1 + 5 = 1.2V1 + 4
0.4V1 = 1
V1 = 2.5 cm³
x = 0.8*2.5
x = 2.00 g