Question

which is the balanced equation for $v_2o_5 + cas \
ightarrow cao + v_2s_5$?\
$\bigcirc$ $v_2o_5 + cas \
ightarrow cao + v_2s_5$\
$\bigcirc$ $5v_2o_5 + 5cas \
ightarrow 10cao + 5v_2s_5$\
$\bigcirc$ $3v_2o_5 + 3cas \
ightarrow 3cao + 3v_2s_5$\
$\bigcirc$ $v_2o_5 + 5cas \
ightarrow 5cao + v_2s_5$

Explanation:

Step1: Analyze each element

First, list the number of each atom on both sides for each option. Let's check V, O, Ca, S.

For the original unbalanced equation: \( V_2O_5 + CaS
ightarrow CaO + V_2S_5 \)

Option 1: \( V_2O_5 + CaS

ightarrow CaO + V_2S_5 \)

• V: 2 on left, 2 on right.
• O: 5 on left, 1 on right. Not balanced.

Option 2: \( 5V_2O_5 + 5CaS

ightarrow 10CaO + 5V_2S_5 \)

• V: 10 on left, 10 on right.
• O: 25 on left, 10 on right. Not balanced.

Option 3: \( 3V_2O_5 + 3CaS

ightarrow 3CaO + 3V_2S_5 \)

• V: 6 on left, 6 on right.
• O: 15 on left, 3 on right. Not balanced.

Option 4: \( V_2O_5 + 5CaS

ightarrow 5CaO + V_2S_5 \)

• V: 2 on left, 2 on right.
• O: 5 on left, 5 (from 5CaO) on right.
• Ca: 5 on left (from 5CaS), 5 on right (from 5CaO).
• S: 5 on left (from 5CaS), 5 on right (from \( V_2S_5 \)). All balanced.

Step2: Confirm the balanced equation

After checking each element's count, the fourth option has equal numbers of each atom on both sides.

Answer:

\( V_2O_5 + 5CaS
ightarrow 5CaO + V_2S_5 \) (the last option among the given choices)