The slot covers on a computer reduce the dust build up inside the computer. So the slot covers should be present in proper place.The missing covers can disrupt the airflow design of the case and cause overheating problems.
There are two types of water hardness: temporary and permanent hardness. Temporary hardness is due to the presence of calcium hydrogen carbonate Ca(HCO3)2(aq) and magnesium hydrogen carbonate Mg(HCO3)2(aq).