What is the empirical formula of a compound that contains 43.38% sodium, 11.33% carbon, and 45.29% oxygen?
Na2CO3
Answer : B) In step 2, there was a chemical change which was observed in sugar.
Explanation : In A step 2 there was a physical change that was seen. By just boiling the dissolved salt solution salt was obtained. Therefore, it is a physical change. In B step 2 there was a chemical change seen as sugar solution was thickened and turned brown. It was not obtained in its original form; there was a chemical reaction that took place during sugar evaporation. As chemical change is the one where the reaction is irreversible.
Therefore only in B step 2 there was a chemical change that was observed.
The number of atoms in 30.0 g of K would be 4.632 x 
atoms.
<h3>Avogadro's number</h3>
1 mole of a substance contains 6.022 x atoms.
Mole of 30.0 g of K potassium = 30/39
= 0.7692 moles
Hence, 0.7692 moles of K would contain
0.7692 x 6.022 x atoms.
= 4.632 x atoms.
More on Avogadro's number can be found here: brainly.com/question/1445383
Answer:
2.677 J/g°C
Explanation:
Quantity of heat required to raise the temperature of the metal,
Q = mc∆T
where m is the mass of the metal, c is the metal's specific heat capacity, and ∆T is the change in temperature that accompanies the heat transfer process
20.0J = 50.0g × c × 150°C
c = 20.0J/(50.0g × 150°C)
c = 2.677 J/g°C
