Răspuns:
0,03kg de gaz lampant
Explicație:
[tex]m_{apa} = 5L = 5kg\\c_{apa} = 4190 \frac{J}{kg * K} \\Q_{necesar} = m_{apa} * c_{apa} * (T_{2} - T_{1} )\\Q_{necesar} = 5 * 4190 * (60-20) = 838000 J\\Q_{degajat}= q * m_{gaz} \\Q_{util} = Q_{degajat} * 0.6 = 0.6 * q * m_{gaz}\\=> m_{gaz} = \frac{Q_{util}}{0.6 * q} \\Q_{necesar}=Q_{util}\\=> m_{gaz} = \frac{Q_{necesar}}{0.6 * q} \\\\m_{gaz} = \frac{838000}{0,6 * 46 * 10^{6} } = 0,03 kg[/tex]
