mohon bantuannya ya temaan

n = w/Mr

n = 2.14/(14 + 4 + 35.5)

n = 0.04 mol

Q = m c ΔT

Q = (100)(4.18)(23.5 - 27)

Q = -1463 Joule

ΔH = -Q/n

ΔH = -(-1463)/0.04

ΔH = +36575 Joule (endoterm)

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CH4 + 2O2 → CO2 + 2H2O

n = w/Mr

n = 32/16

n = 2 mol

Q = m c ΔT

Q = (4000)(4.2)(90.5 - 25.5)

Q = 1.092 * 10^6 Joule

entalpi pembakaran gas metana adalah

ΔH = -Q/n

ΔH = -(1.092 * 10^6)/2

ΔH = -546000 Joule/mol

massa air = 100 mL = 100 gram
massa NH4Cl = 2,14 gram
Mr = 53,5
c = 4,2
ΔH = ...................................?

mol = massa/Mr 
       = 2,14/53,5
       = 0,04 mol

ΔT = 27 - 23,5
      = 3,5°C

Q = m.c.ΔT 
    = 100 x 4,2 x 3,5
    =1470 joule = 1,470  kJ

ΔH = Q/mol
      = 1,470/0,04
      = 36,75 kJ/mol (C)

"semoga membantu :)