Which TWO of the following options are TRUE about atomic mass and mass number? A - The mass number is always the atomic mass rounded to the nearest whole number.
B - The atomic mass of an element is always the same no matter what the mass number of that particular atom is.
C - Mass number is always equal to the atomic number multiplied by 2.
D - The mass number is written on the periodic table.
E - Atomic mass is calculated by weighted atomic average using all the isotope data available.
F - Atomic mass and mass number are the same thing.
G - Mass number is equal to the sum of protons and electrons in an atom.

PLEASE ANSWER FAST

nacl or sodium chloride is an ionic compound. this is because an ionic compound pertains to a compound that consists of positively and negatively charged ions. in this case, na (sodium) has a tendency to lose one electron when it reacts with with other atoms, so the resulting sodium ion contains 11 protons and 10 electrons, thus making it positively charged (na+), when chlorine reacts, it usually gains one electron to form an ion called chloride, thus making it negatively charged ( since the ions are oppositely charged, they attract.

answer : third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol

explanation :

let us write down the given equations

equation 1 :

equation 2 :

equation 3 :

let us use hess's law to find out which 2 equations can be added to get the third equation.

let us reverse equation 2 and multiply it by 2. the new equation that we get is,

equation 4 :

let us add equation 1 & 4

the above equation is similar to equation 3 but has different value for dhrxn.

therefore third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol