Answer:
mass number = 18
Explanation:
The mass number is the total amount of protons and neutrons in an atom. Therefore, if there are 8 protons and 10 neutrons, the mass number is 18 (8 + 10 = 18).
Answer:
[CaSO₄] = 36.26×10⁻² mol/L
Explanation:
Molarity (M) → mol/L → moles of solute in 1L of solution
Let's convert the volume from mL to L
250 mL . 1L/1000 mL = 0.250L
We need to determine the moles of solute. (mass / molar mass)
12.34 g / 136.13 g/mol = 0.0906 mol
M → 0.0906 mol / 0.250L = 36.26×10⁻² mol/L
Answer:
a) the minimun of acetic anhydride required for the reaction is 2.175 g (CH3CO)2O
b) V acetic anhydride = 2.010 mL
Explanation:
C6H4OHCOOH + (CH3CO)2O ↔ C9H8O4 + C2H4O2
⇒ mol salicylic acid = 2.94 g C6H4OHCOOH * ( mol C6H4OHCOOH / 138.121 g ) = 0.0213 mol C6H4OHCOOH
⇒ mol acetic anhydride = 0.0213 mol C6H4OHCOOH * ( mol (CH3CO)2O / mol C6H4OHCOOH ) = 0.0213 mol (CHECO)2O
⇒ g acetic anhydride = 0.0213 mol * ( 102.1 g/mol ) = 2.175 g CH3CO)2O
b) V = 2.175 g (CH3CO)2 * ( mL / 1.082 g ) = 2.010 mL (CH3CO)2O
Answer:
-<em>9</em><em>.</em><em>6</em><em>7</em><em>5</em>
Explanation:
<em>c</em><em>o</em><em>r</em><em>r</em><em>e</em><em>c</em><em>t</em><em> </em><em>m</em><em>e</em><em> </em><em>i</em><em>f</em><em> </em><em>i</em><em>m</em><em> </em><em>w</em><em>r</em><em>o</em><em>n</em><em>g</em><em>.</em><em>!</em><em>!</em><em> </em><em />
1st and 4th options are suitable answers, as these 2 changes are not exactly physical changes as it cant return back to original form and as well as its not cooling, so I feel its 1st and 4th options
