Answer:
8.55 × 10³ cal
Explanation:
Step 1: Given and required data
- Specific heat of water (c): 1 cal/g.°C
- Initial temperature: 22.7 °C
- Final temperature: 38.8 °C
Step 2: Calculate the temperature change (ΔT)
ΔT = Final temperature - Initial temperature = 38.8 °C - 22.7 °C = 16.1 °C
Step 3: Calculate the heat required (Q)
We will use the following expression.
Q = c × m × ΔT
Q = 1 cal/g.°C × 531 g × 16.1 °C = 8.55 × 10³ cal
Answer:
A. 0.603
Explanation:
Mass fraction of an element in a substance = mass of that element / total mass of the substance.
Mass of magnesium = 24.3g/mol
Mass of oxygen = 16g/mol
Total mass of MgO = 24.3+16 = 40.3g/mol
Hence, the mass fraction of magnesium in Magnesium oxide =
24.3/40.3
= 0.6029
= 0.603
Another way is to divide the percentage by mass of magnesium by 100 i.e. 60.3% = 60.3/100
= 0.603
Answer:
The given reaction in your problem is the ionic equation for an acid (carbonic acid) reacting with a base (sodium hydroxide). All components of the reaction are then written in ionic form except for reactant weak electrolytes and the driving force product compound of the reaction (H2O). See following explanation.
Explanation:
Metathesis Rxn: molecular equation of rxn
H₂CO₃(aq) + 2NaOH(aq) => Na₂CO₃(aq) + 2H₂O(l)
Ionic Equation: shows all components of the reaction
H₂CO₃(aq) + 2Na⁺(aq) + 2OH⁻(aq) => 2Na⁺(aq) + CO₃²⁻(aq) + 2H₂O(l)
H₂CO₃(aq) wk. electrolyte and H₂O(l) driving force compound are not shown ionized in ionic equation. Only strong electrolytes that ionize 100%; i.e., salts and strong acids and bases.
Net Ionic Equation: shows only the reactive components without the spectator ions (nonreactive components), in this case, the Na⁺(aq) ions.
H₂CO₃(aq) + 2OH⁻(aq) => CO₃²⁻(aq) + 2H₂O(l)
