Question

Determine the water equivalent of $4.5\text{kg}$ of antimony. Take specific heat of antimony and water as $0.210\text{kJ/kg K}$ and $4.20\text{kJ/kg K}$ respectively.

• A. $0.225\text{kg}$
• B. $0.208\text{kg}$
• C. $0.325\text{kg}$
• D. $0.608\text{kg}$

Answer 1

The correct option is A $0.225\text{kg}$

Given, mass of antimony [kg] $=4.5\text{kg}$
$C_A=$ specific heat of antimony $=0.210\text{kJ/ kg K}$
$C_w=$ specific heat of water $=4.2\text{kJ/ kg K}$
Let $m_w$ be the water equivalent of antimony.
From equating heat capacities, we get
$\Rightarrow m_A{C}_A=m_w{C}_w$
$\Rightarrow m_w=\frac{m_A{C}_A}{C_w}$
$\Rightarrow m_w=\frac{4.5\times 0.210}{4.20}$
$\Rightarrow m_w=0.225\text{kg}$
Hence answer (a) is correct.