<span>It is because air is a poor conductor of heat. Good luck ;)</span>
Answer:
endothermic change occurs
Explanation:
photosynthesis, is an endothermic reaction in which energy is absorbed from the surrounding.
hope this helps
Answer:
Endothermic
It absorbs heat
1.20 × 10³ kJ
Explanation:
Let's consider the following thermochemical equation.
2 H₂O(l) → 2 H₂(g) + O₂(g) ΔH = 572 kJ
Since ΔH > 0, the reaction is endothermic, that is, it absorbs heat when H₂O reacts.
572 kJ are absorbed when 36.03 g of water react. The heat absorbed when 75.8 g of H₂O react is:
75.8 g H₂O × (572 kJ/36.03 g H₂O) = 1.20 × 10³ kJ
Answer:
e. 3.08 x 10⁻² mol of ions.
Explanation:
- Every 1.0 mole of any compound contains Avogadro's number of molecules (6.022 x 10²³).
- We can get the no. of moles of NiCl₂ using cross multiplication:
1.0 mol NiCl₂ contains → 6.022 x 10²³ molecules.
??? mol NiCl₂ contains → 6.188 x 10²¹ molecules.
∴ The no. of moles of NiCl₂ = (1.0 mol)(6.188 x 10²¹ molecules)/(6.022 x 10²³ molecules) = 1.028 x 10⁻² mol.
- NiCl₂ is ionized according to the equation:
NiCl₂ → Ni²⁺ + 2Cl⁻.
Which means that every 1.0 mol of NiCl₂ is ionized to produce 3.0 moles (1.0 mol of Ni²⁺ and 2 moles of Cl⁻).
<em>∴ The total moles of ions are released</em> = 3 x 1.028 x 10⁻² mol = <em>3.083 x 10⁻² mol of ions.</em>
Answer:
<em> 14, 508J/K</em>
ΔHrxn =q/n
where q = heat absorbed and n = moles
Explanation:
<em>m = mass of substance (g) = 0.1184g</em>
1 mole of Mg - 24g
<em>n</em> moles - 0.1184g
<em>n = 0.0049 moles.</em>
Also, q = m × c × ΔT
<em> Heat Capacity, C of MgCl2 = 71.09 J/(mol K)</em>
<em>∴ specific heat c of MgCL2 = 71.09/0.0049 (from the formula c = C/n)</em>
<em>= 14, 508 J/K/kg</em>
ΔT= (final - initial) temp = 38.3 - 27.2
= 11.1 °C.
mass of MgCl2 = 95.211 × 0.1184 = 11.27
⇒ q = 11.27g × 11.1 °C × <em>14, 508 j/K/kg </em>
<em>= 1,7117.7472 J °C-1 g-1</em>
<em />
<em>∴ ΔHrxn = q/n</em>
<em>=1,7117.7472 ÷ 0.1184 </em>
<em>= 14, 508J/K</em>
