Answer:
The correct answer is d. As the chocolate bar changes from a solid to a liquid the particles move around more.
Explanation:
When a chocolate bar melts, it suffers a <u>physical</u> change: a change of state from solid to liquid. In the liquid state, the particles move around more, because they have more kinetic energy (more velocity) and more freedom to move than in solid state. Thus, as the solid became into a liquid, the particles move more.
Answer:
On the left side of calcium atom.
Explanation:
There are two dots are present on the left side of calcium atom which represents the unpaired electrons present in the outermost shell. This structure is presented by Lewis in order to show the number of unpaired electrons in the atom. if the calcium atom loses these two electron during a chemical reaction so the two dots disappear and the calcium atom is now stable.
Answer:
two electrons are lost by magnesium to form magnesium ion (Mn+2) and gained by two oxygen atoms (O-)
Answer: 1.99 x 10²² molecules H2
Explanation:First we will solve for the moles of H2 using Ideal gas law PV= nRT then derive for moles ( n ).
At STP, pressure is equal to 1 atm and Temperature is 273 K.
Convert volume in mL to L:
750 mL x 1 L / 1000 mL
= 0.75 mL
n = PV/ RT
= 1 atm ( 0.75 L ) / 0.0821 L.atm/ mole.K ( 273 K)
= 3.3x10-² moles H2
Convert moles of H2 to atoms using Avogadro's Number.
3.3x10-² moles H2/ 6.022x10²³ atoms H2 / 1 mole H2
= 1.99x10²² atoms H2
