Answer:
10.3 g of oxygen are formed when 26.4 g of potassium chlorate is heated
Explanation:
This is the balanced equation:
2KClO₃(s) → 2KCl(s) + 3O₂(g)
Ratio beteween the salt and oxygen is 2:3
Molar mass of KClO₃ = 122.55 g/m
Let's find out the moles of salt
Mass / Molar mass
26.4 g /122.55 g/m = 0.215 moles
So, this is the final rule of three:
If 2 moles of KClO₃ make 3 moles of oxygen
0.215 moles of KClO₃ make (0.215 .3) /2 = 0.323 moles of O₂ are produced
Molar mass O₂ = 32 g/m
Moles . molar mass = mass
0.323 m . 32g/m = 10.3 g
D. All of the above are indicators of chemical change
Answer:
2-4 mm height of capillary tube.
Explanation:
Sample should be around 2-4 mm in height.
It should be packed well so that it does not have air packets that caues the lowering of melting point.
If you take greater amount, then there will be needed more heat, resulting a wide range of melting point.
Answer:
ΔH = 2.68kJ/mol
Explanation:
The ΔH of dissolution of a reaction is defined as the heat produced per mole of reaction. We have 3.15 moles of the solid, to find the heat produced we need to use the equation:
q = m*S*ΔT
<em>Where q is heat of reaction in J,</em>
<em>m is the mass of the solution in g,</em>
<em>S is specific heat of the solution = 4.184J/g°C</em>
<em>ΔT is change in temperature = 11.21°C</em>
The mass of the solution is obtained from the volume and the density as follows:
150.0mL * (1.20g/mL) = 180.0g
Replacing:
q = 180.0g*4.184J/g°C*11.21°C
q = 8442J
q = 8.44kJ when 3.15 moles of the solid react.
The ΔH of the reaction is:
8.44kJ/3.15 mol
= 2.68kJ/mol
Answer is: glycerol because it is more viscous and has a larger molar mass.
Viscosity depends on intermolecular interactions.
The predominant intermolecular force in water and glycerol is hydrogen bonding.
Hydrogen bond is an electrostatic attraction between two polar groups in which one group has hydrogen atom (H) and another group has highly electronegative atom such as nitrogen (like in this molecule), oxygen (O) or fluorine (F).
