All elements have a ΔHf of 27314.1840 kJ/mole at standard temperature and pressure.

1 answer:

4 0

Answer: All elements have a ΔHf of 0 (zero) at standard temperature and pressure.

Standard ΔHf of formation is the standard enthalpy (heat) of formation of the compound. It is defined as the change of enthalpy when one mol of compound is formed in its standard state from the elements in their standard state.

Then, as the elements are already in their standard state, there is not any change and the standard enthalpy of an element in its standard state is, by definition, zero.

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Calcium oxide and oxygen gas are produced by the thermal decomposition of limestone in the reaction CaCO (s) CaO(s) + CO (g). Wh

kozerog [31]

The mass of lime that can be produced from 4.510 Kg of limestone is calculated as below

calculate the moles of CaCO3 used

that is moles =mass/molar mass
convert Kg to g = 4.510 x1000 =4510g
= 4510 / 100 =45.10 moles
CaCO3 = CaO +O2

by use of mole ratio between CaCO3 to CaO (1:1) the moles of CaO is also= 45.10 moles
mass of CaO = moles x molar mass

45.10 x56 = 2525.6 g of CaO

6 0

4 years ago

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Sketch two amino acids side-by-side, on one of them label the functional groups, then show how the two can be joined together.

Alinara [238K]

Answer : The sketch of two amino acids side by side are shown below.

Explanation :

Amino acid : Amino acid are the acid that contains two functional groups which are carboxylic group, $-COOH$ and ammine group, $-NH_2$ .

When the two or more that two amino acids join together with the help of peptide bond, they produces polypeptide chain or protein.

The bond present between the two amino acid is called a peptide bond.

The peptide bond is a chemical bond that is formed between the two molecules when the nitrogen of one amino acid react with the carbon of another amino acid by releasing a water molecule.

Hence, the sketch of two amino acids side by side are shown below.