Answer:
1.02mole
Explanation:
The reaction equation is given as:
2NaOH + H₂SO₄ → Na₂SO₄ + 2H₂O
Given:
Mass of H₂SO₄ = 50g
Unknown:
Number of moles of NaOH = ?
Solution:
To solve this problem, we first find the number of moles of the acid given;
Number of moles = 
Molar mass of H₂SO₄ = 2(1) + 32 + 4(16) = 98g/mol
Now;
Number of moles = 
= 0.51mole
From the balanced reaction equation:
1 mole of H₂SO₄ will be neutralized by 2 mole of NaOH
0.51 mole of H₂SO₄ will be neutralized by 2 x 0.51 = 1.02mole of NaOH
Answer: 2.88×
atoms 
Explanation: First, using stoichiometry, we must convert this from grams to moles, then from moles to atoms.
1. For the first step, we should also look at the periodic table to find the molar mass of the compound, then use that as the denominator.
2. Now that it is converted to moles, we must convert it to atoms by multiplying it by Avogadro's number.
With this information, we know that there are 
total atoms in 0.680 grams 
.
I hope this helps! Pls give brainliest!! :)
Answer: The periodic table
Explanation: Demetri Mendeleyev is famous for developing the periodic table. He introduced it in 1869.
Answer is: 4) The same subscripts are on each side of the equation.
For example, balanced chemical reaction:
2Mg + O₂ → 2MgO.
1) The same number of atoms is on each side of the equation: two magnesium atoms and two oxgen atoms.
2) The formulas for all substances are correct: in magnesium oxide (MgO), magnesium has oxidation number +2 and oxygen -2, so formula is good, because compound must be neutral.
3) The same mass is represented on each side of the equation: because there is same number of atoms, the mass is the same.
4) The same subscripts are on each side of the equation: oxygen does not have same subscripts.
