12, if the decimal is over five, round up. If it's not, round down. Not sure what you mean by significant figures.
I'm going to suppose you want the adjusted chemical reaction, using the formulas of the compounds. You can see it in the image attached.
Explanation:
The reason as to why the dark chocolate always melted the fastest was because of it's colour. It was a darker shade than the milk and white chocolate and the sun naturally absorbs dark colours therefore it melted faster.

https://prezi.com › science-project
Alpha partical is a He nucleus. When decaying alpha particle mass is reduced by 4 and atomic number is reduced by 2.
The actual element which has 102 protons is No (Nobelium).
Since it has 167 neutrons, the mass = protons + neutrons = 102 + 167 = 269
after an alpha decay, the new element formed has 100 protons which is Fm ( Fermium)
the alpha decaying equation is,
₁₀₂²⁶⁹No → ₁₀₀²⁶⁵Fm + ₂⁴α + heat
the total mass and the atomic number( numbe rof protons) must be equal in both sides.
