A. How many electrons are in a neutral atom of lithium?
B.
How many neutrons are in an atom of Mg-25?
C.
What is the mass number of an atom with 5 protons and 7 neutrons?
D.
When an atom is charged, it is called an ion. How many electrons are in O2-?
E.
How many electrons are in Mg2+?

when [oh-] is 10-5  m, and [h3o+] is 10-9  m, the poh is 5 and ph is 9. again in both cases the sum of ph and poh is 14. however, the hydrogen ion concentration is not always going to be equal to exactly 1 x 10 raised to a negative number. for example, we skipped over the value of 2.0 x 10-7.

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.

yes

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