Problem 25 - Chemistry An Atoms First Approach

Question

When jump-starting a car with a dead battery, the ground jumper should be attached to a remote part of the engine block. Why?

Step-by-Step Solution

Answer

When jump-starting a car with a dead battery, the ground jumper should be attached to a remote part of the engine block because it helps prevent sparking near the battery, which can be dangerous due to the potential explosion of hydrogen gas released from the battery. Additionally, it ensures a stable ground connection, reducing the risk of damage to electrical components and improving current transfer between vehicles for effective charging of the dead battery.

Step 1: Connect the positive jumper cable

First, connect the positive (red) jumper cable to the positive terminal on the dead battery. Make sure the cable is securely attached.

Step 2: Connect the other end of the positive jumper cable

Connect the other end of the positive (red) jumper cable to the positive terminal on the working battery of the assisting vehicle.

Step 3: Connect the negative jumper cable

Connect the negative (black) jumper cable to the negative terminal on the working battery of the assisting vehicle. Ensure the cable is securely attached.

Step 4: Attach the ground jumper to the engine block

Instead of connecting the other end of the negative (black) jumper cable to the negative terminal on the dead battery, attach it to a remote part of the engine block (an unpainted metal surface). Doing this helps in preventing sparking near the battery, as hydrogen gas released from a battery might be explosive. Also, it ensures a stable ground connection, reducing the risk of damage to electrical components and improving current transfer between vehicles.

Step 5: Start the assisting vehicle

Start the engine of the assisting vehicle and let it run for a few minutes to charge the dead battery.

Step 6: Start the vehicle with the dead battery

Attempt to start the vehicle with the dead battery. If it starts, let it run for a few minutes to further charge the battery. If it does not start, wait a few more minutes and try again.

Step 7: Disconnect the jumper cables

Once the dead-battery vehicle is running, disconnect the jumper cables in the reverse order of how you connected them. Start with the ground (black) cable from the engine block, then the black cable from the assisting vehicle, followed by the red cable from the assisting vehicle, and finally the red cable from the previously dead battery. Be cautious not to let the cable clamps touch each other while they are still connected to vehicles.