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 cards have a four-digit CVV located on the front of the card, just above and to the right of your account number. For all four card issuers, the CVV is printed on the card, rather than embossed. At first glance, itâs hard to see how CVV numbers help keep online transactions secure.