Glass is a hard substance that consists of sand, soda ash and limestone. When these substances are heated together, their molecules bond to form the substance we know as glass. We use glass for many purposes, and glass bottles have become a popular method of storage, as well as being used in chemical experiments.
Answer:
Mole fraction = 0,0166
Explanation:
Mole fraction is defined as mole of a compound per total moles of the mixture. In the solution, the solute is fructose and the solvent is water. That means you need to find moles of fructose and moles of water.
The molecular mass of fructose is 180,16g/mol and mass of water is 18,02 g/mol. Using these values:
91,7g fructose × (1mol / 180,16g) = <em>0,509 moles of fructose</em>
545g water × (1mol / 18,02g) = <em>30,24 moles of water</em>
Thus, mole fraction of fructose is:
<em>Mole fraction = 0,0166</em>
I hope it helps!
The concentration of the drug stock solution is 1.5*10^-9 M i.e. 1.5 * 10^-9 moles of the drug per Liter of the solution
Therefore, the number of moles present in 1 ml i.e. 1*10^-3 L of the solution would be = 1 *10^-3 L * 1.5 * 10^-9 moles/1 L = 1.5 * 10^-12 moles
1 mole of the drug will contain 6.023*10^23 drug molecules
Therefore, 1.5*10^-12 moles of the drug will correspond to :
1.5 * 10^-12 moles * 6.023*10^23 molecules/1 mole = 9.035 * 10^11 molecules
The number of cancer cells = 2.0 * 10^5
Hence the ratio = drug molecules/cancer cells
= 9.035 *10^11/2.0 *10^5
= 4.5 * 10^6
When ice melts, the physicals state changes from solid to liquid. The energy or the heat required (q) required to change a unit mass (m) of a substance from solid to liquid is known as the enthalpy or heat of fusion (ΔHf). The variables; q, m and ΔHf are related as:
q = m * ΔHf
the mass of ice m = 65 g
the heat of fusion of water at 0C = ΔHf = 334 J/g
Therefore: q = 65 g * 334 J/g = 21710 J
Now:
4.184 J = 1 cal
which implies that: 21710 J = 1 cal * 21710 J/4.184 J = 5188.8 cal
Hence the heat required is 5188.8 cal or 5.2 Kcal (approx)
Answer:
Sr(s) + C(s) + 3/2 O₂(g) → SrCO₃(s)
Explanation:
The standard enthalpy of formation (ΔH°f) is the energy involved in the formation of 1 mole of a substance from its elements in their most stable states. The chemical equation for the formation of SrCO₃(s) is the following.
Sr(s) + C(s) + 3/2 O₂(g) → SrCO₃(s)
