Answer:

Explanation:
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In this case, since the energy involved during a heating process is shown below:

Whereas the specific heat of water is 4.184 J/(g°C), we can compute the heated mass of water by the addition of 11.9 kJ (11900 J) of heat as shown below:

Thus, by plugging in, we obtain:

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NaCl is an ionic compound because Chlorine is a nonmetal and Sodium is a metal (Alkali Metal Group)
Actually, no. While their mass may be the same (1kg), the volume of lead is a lot smaller than that of feathers. As there is the same mass stuffed in a smaller space, it must be denser. The density of water is 1 g/cm3, so if the density of the lead is more than 1g/cm3, it has to sink