Answer:
C
Explanation:
If the enthalpy change (i.e. Δ<em>H</em>) of a reaction is negative, then the reaction releases heat and is hence exothermic.
Hence, our answer is C.
Conversely, if Δ<em>H</em> is positive, the reaction absorbs heat and is endothermic.
Δ<em>H</em> tells us nothing about the speed of the reaction.
While Δ<em>H</em> influences free-energy change (Δ<em>G</em> = Δ<em>H</em> - <em>T</em>Δ<em>S</em>), we cannot predict the sign of Δ<em>G</em> given only Δ<em>H </em>(recall that a reaction is spontaneous if Δ<em>G</em> < 0).
there are 1023 atoms in pure aluminium
An atom is a solid sphere is now considered scientifically inaccurate.
So the correct answer is B.
Hope this helps,
Davinia.
Answer:
a) [H3O+] = 1.00 E-10 M ⇒ [OH-] = 1.0 E-4 M
b) [H3O+] = 1.00 E-4 M ⇒ [OH-] = 1.0 E-10 M
c) [H3O+] = 9.90 E-6 M ⇒ [OH-] = 1.0 E-9 M
Explanation:
- 14 = pH + pOH
- pH = - Log [H3O+]
a) [H3O+] = 1.00 E-10 M
⇒ pH = - Log(1.00 E-10) = 10
⇒ pOH = 14 - 10 = 4
⇒ 4 = - Log[OH-]
⇒ [OH-] = 1.0 E-4 M
b) [H3O+] = 1.00 E-4 M
⇒ pH = 4
⇒ pOH = 10
⇒ [OH-] = 1.0 E-10 M
c) [H3O+] = 9.90 E-6 M
⇒ pH = 5
⇒ pOH = 9
⇒ [OH-] = 1.0 E-9 M
Answer:
15.5 gm
Explanation:
What is the mass of phosphorus that contains twice the number of atoms found in 14 g of iron?
[Relative atomic mass : P = 31; Fe = 56]
14 gm Fe = 14gm/ 56 gm/mole = 14 mole gm/56gm = 14/56 mole
0.25 moles
2 X 0.25 = 0.5 moles
1 mole P = 31 gm
so
0.5 moles P =31/2 =15.5 gm
