Answer:
32
Explanation:
0.56dm of gas has 0.8g
22.4dm of gas Z has a mass of 22.4/0.56X0.8
the relative molecular mass of gas Z is 32
Answer:-
Solution:- As is clear from the given Ka value, Cinnamic acid is a weak acid. let's calculate the moles of acid and KOH added to it from their given molarities and mL.
For KOH, 
= 0.002 mol
For Cinnamic acid, 
= 0.003 mol
Acid and base react as:
The reaction takes place in 1:1 mol ratio. Since the moles of acid are in excess, the acid is still remaining when all the kOH is used.
0.002 moles of KOH react with 0.002 moles of Cinnamic acid to form 0.002 moles of potassium cinnamate. Excess moles of Cinnamic acid = 0.003 - 0.002 = 0.001
As the solution have weak acid and it's salt(or we could say conjugate base), it is a buffer solution and the pH of the buffer solution could easily be calculated using Handerson equation:
pKa could be caluted from given Ka value using the formula:
pKa = - log Ka
pKa = 4.44
let's plug in the values in Handerson equation and calculate the pH:
pH = 4.44+0.30
pH = 4.74
So, the first choice is correct, pH is 4.74.
if the product has lesser energy than the reactants it means enthalpy change value is positive.so it is endothermic reaction where the heat is absorbed.so kcl will formation will have positive enthalpy change .
The specific heat in, J /g °C of copper is 0.386J/g°C
HOW TO CALCULATE SPECIFIC HEAT CAPACITY OF A SUBSTANCE:
- The specific capacity of a substance can be calculated using the following formula:
Q = m × c × ∆T
Where;
Q = quantity of heat absorbed or released (J)
m = mass of substance (g)
∆T = change in temperature (°C)
c = specific heat capacity (J/g°C)
For a colorimeter, the following equation applies:
m.c.∆T (water) = - m.c.∆T (metal)
m = 50g
c = 4.184 J/g°C
∆T = 29.2 - 26°C = 3.2°C
m = 70g
c = ?
∆T = 29.2 - 54°C = -24.8°C
m.c.∆T (water) = - m.c.∆T (metal)
50 × 4.184 × 3.2 = -(70 × c × -24.8)
669.44 = 1736c
c = 669.44 ÷ 1736
c = 0.386J/g°C
Therefore, the specific heat in, J /g °C of copper is 0.386J/g°C
Learn more at: brainly.com/question/16787162?referrer=searchResults
Answer:true
Explanation:
In covalent bond, lone pair of electrons are shared by the reacting species inorder to achieve a stable duplet or octet condition.as a result, molecules and not ions are formed
