Copper pennies (95% copper, 5% zinc) weigh 3.11 grams. Modern zinc pennies (97.5% zinc, 2.5% copper) weigh 2.5 grams.
Very, very little. All pennies made since 1982 (some 1982 coins are made out of a 95% copper bronze alloy, others are copper-plated zinc) are copper plated zinc and only contain a very small amount of copper. Since this isn't an alloy and it wears off during use, it really isn't possible to calculate just how much copper is in there, but suffice to say it isn't much at all.
Today, a penny is made of primarily zinc with a thin coating of copper. This composition is known as copper-plated zinc.
The weight of a zinc 1983 penny is 2.5 grams, while the weight of a copper 1983 penny is 3.11 grams.
A post-1982 penny is made of 97.5% zinc and 2.5% copper. The composition changed from primarily copper to primarily zinc in order to reduce production costs.
In 1961 pennies were made of 95% copper and 5% zinc.
If by formula you mean composition, a post-1982 penny is 97.5% Zinc and 2.5% Copper by mass.
Copper
There is 97.5 percent zinc in a penny and 2.5 percent copper
A 1983 penny is made of 95% copper and 5% zinc. The actual weight of copper in a 1983 penny is approximately 2.5 grams.
no
A zinc penny would dissolve in phosphoric acid, not a copper penny. Zinc reacts with phosphoric acid to form zinc phosphate and hydrogen gas. This reaction does not occur with copper, as copper is a more stable metal and does not react with phosphoric acid in the same way.
zinc is 97.5% of the penny and copper is 2.5% of the penny
Very, very little. All pennies made since 1982 (some 1982 coins are made out of a 95% copper bronze alloy, others are copper-plated zinc) are copper plated zinc and only contain a very small amount of copper. Since this isn't an alloy and it wears off during use, it really isn't possible to calculate just how much copper is in there, but suffice to say it isn't much at all.
Today, a penny is made of primarily zinc with a thin coating of copper. This composition is known as copper-plated zinc.
The weight of a zinc 1983 penny is 2.5 grams, while the weight of a copper 1983 penny is 3.11 grams.
Copper or zinc
Current pennies (since 1982) are copper-plated zinc, so the answer is it's covered in copper. The penny is 2.5% copper, and 97.5% zinc. See the related links for a history of penny composition over the years.