3.A thin strip of iron with a mass of 15.5g is placed into a solution containing 21.0g of copper (II) sulfate and copper begins to form. After some times, the reactions stops because
all the copper (II) sulfate has reacted. The iron strip is found to have a mass of 8.5g. The mass
of copper formed is found to be 8.60g. What mass of iron (II) sulfate has been formed in the
reaction?​

b is the correct answer

mark me brainliest and hope this

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer

answer:

the answer is 6 valence electrons.

explanation:

valence is the # of electrons on the outer most shell of an atom.

oxygen has 6.

although, the valency of oxygen is 2, because it only needs to make 2 covalent bonds, or gain 2 electrons, to achieve the stable octet configuration of a noble gas.

that's it!

if you need further assistance, let me know: )

~ trueboss72

answer: they produce more slow than unicellular organisms.