Answer:
this is answers to the second picture
Explanation:
1- energy
2- structure
3- reaction
4- substance
5- reactants
6- products
7- changed
8- At first there is no reaction because of the protective oxide coating on the aluminum. But soon an exothermic reaction between bromine and aluminum causes brown fumes of bromine to be given off. But as a new substance, aluminum bromide is produced. White smoke is produced.
9- heated to 120 degrees Celsius it melts and first forms a pale-yellow liquid.
In this form the atoms are covalently bonded, and the liquid can flow easily. However, heated up beyond 150 degrees Celsius, the result is a dark red
10- When a chemical change occurs it is more difficult to revert the substance back to its original state. (To be honest I don't know)
In a plastic sheet protector
You'll want to add three amounts of heat.
(1) Specific heat of lowering the temperature from -135°C to the melting point -114°C
(2) Latent heat of fusion/melting
(3) Specific heat of elevating the temperature from -114°C to -50°C
(1) E = mCΔT = (25 g)(0.97 J/g·°C)(1 kJ/1000 J)(-114 - -135) = 0.509 kJ
(2) E = mΔH = (25 g)(5.02 kJ/mol)(1 mol/46.07 g ethanol) = 2.724 kJ
(3) E = mCΔT = (25 g)(2.3 J/g·°C)(1 kJ/1000 J)(-50 - -114) = 3.68 kJ
<em>Summing up all energies, the answer is 6.913 kJ.</em>
Balance the equation: 2Na + S --> Na2S
Using the given amount of the reactants in the reaction, calculate the amount of the product:
45.3g Na x (1 mol/22.99 g)= 1.97 mol of Na
105f S x (1 mol/ 32.06g) = 3.28 mol of S
The limiting reactant would be Na:
<span>1.97 mol Na x (1 mol Na2S/ 2 mol Na) x (78.04g/mol) = 76.87g of Na2S produced</span>
Physical change .. you cannot undo chemical ... physical is like bending , shattering a mirror , denting something ..
chemical would be rust or something .
