The heat for melting or freezing water, also called the Heat of Fusion (Hf), is 80 calories per gram at 0Â°C, which is the equilibrium temperature. In other words, it is necessary to add 80 calories of energy to melt one gram of ice at 0Â°C.
The CVV Number (Card Verification Value) on your credit card or debit card is a 3 digit number on VISAÂ®, MasterCardÂ® and DiscoverÂ® branded credit and debit cards. On your American ExpressÂ® branded credit or debit card it is a 4 digit numeric code.
American Express prints a 4-digit number (1122 in the example) on the front of the card, above and to the right of the embossed account number. Make sure that you explain this to your customers. To validate the card security code in a transaction, pass the card security code value in the CVV2 parameter in your request.