Answer:
Calculated density = 0.8555g/ mL
Probable identity = Toulene
Explanation:
First off, the substance choices are;
isopropyl alcohol (density 0. 785 g/ mL)
toluene ( density 0.866g/ mL)
So upon calculation, if the density of the liquid substance is equal to either of the substances in the choice, it is that substance.
The relationship between density, mass and volume is given as;
Density = Mass / Volume
Mass = 38.5g
Volume = 45ml
Density = 38.5 / 45 = 0.8555g/ mL
Calculated density = 0.8555g/ mL
Among both substances, it is closest to toluene ( density 0.866g/ mL).
Probable identity = Toulene
Answer:
That's not true. It would in fact be physical.
Explanation:
physical change: some of its physical properties may change but its identity does not
A). Until they have a stable nucleus.
7.5 ppm
<h3>Further explanation</h3>
Given
1000 g of water
0.0075g of Ca²⁺ ion
Required
the concentration in ppm by mass of Ca²⁺
Solution
ppm = part per million
solvent = water ⇒ ppm = 1 mg/L(water density is 1 kg / L) or mg/kg
Convert g to mg of Ca²⁺ ion :
0.0075 g = 7.5 x 10⁻³ g = 7.5 mg
Convert g to kg of water :
1000 g = 1 kg water
So the concentration of Ca²⁺ ion :
= 7.5 mg / 1 kg
= 7.5 ppm
Energy is required to change the phase of a material, with the change in energy either it decreases or increases.
When the phase is changed, the temperature and kinetic energy does not change it stays the same but the internal energy changes.
Internal energy is the sum of chemical potential energy and kinetic energy of the molecules, and when the internal energy changes during a phase change it means average potential energy is changing.
