D. is the answer
hope i could help
Nothing happens because a physical change only changes the appearance of the substance, whereas a chemical change transforms the substance into something completely different.
i.e. (chemical change) wood + fire = ash
(physical change) wood + axe = smaller pieces of wood
<span>The vaporization of br2 from liquid to gas state requires 7.4 k/cal /mol.</span>
The way you calculate the empirical formula is to firstly assume 100g. To find each elements moles you take each elements percentage listed, times it by one mole and divide it by its atomic mass. (ex: moles of K =55.3g x 1 mole/39.1g, therefore there is 1.41432225 moles of Potassium) Once you’ve completed this for every element you list each elements symbol beside it’s number of moles and divide by the smallest number because it can only go into its self once. After you’ve done this, you’ve found your empirical formula, which is the simplest whole number ratio of atoms in a compound. I’ve added an example of a empirical question I completed last semester :)
Answer: 30. 7 moles SO3
31. 3 moles SO2 and 3 moles SO3
Explanation: To solve for this problem use the mole ratio of the substances involved in the reaction.
Solution for number 30:
3.5 moles O2 x 2 moles SO3 / 1 mole O2
= 7 moles SO3
31. 192 g SO2 x 1 mole SO2 / 64 g/ mol SO2
= 3 moles SO2
3 moles SO2 x 2 moles SO3 / 2 moles SO2
= 3 moles SO3