Answer:
The empirical formula for the compound is Na2O
Explanation:
Data obtained from the question include:
Sodium (Na) = 74.2g
Oxygen (O) = 25.8g
We can obtain the empirical formula for the compound as follow:
First, divide the above by their individual molar mass as shown below:
Na = 74.2/23 = 3.226
O = 25.8/16 = 1.613
Next, divide the above by the smallest number
Na = 3.226/1.613 = 2
O = 1.613/1.613 = 1
Therefore, the empirical formula is:
Na2O
Pure water may be identified by its density: it will have the lowwest density of the three solutions, given that the solutes (salt and sugar) increase the density (this is the easiests and quickest way).
You can also measure the freezing points or boling points to identify the pure water because the solutes depress the freezing points and increase the boling points.
To differentiate sugar water and salt water, you can probe which one conducts electricity, because salt water is a conductor (given that it ionizes into Na+ and Cl-) but sugar water is not a conductor.
Answer:
The answer to the question is
The specific heat capacity of the alloy = 1.77 J/(g·°C)
Explanation:
To solve this, we list out the given variables thus
Mass of alloy = 45 g
Initial temperature of the alloy = 25 °C
Final temperature of the alloy = 37 °C
Heat absorbed by the alloy = 956 J
Thus we have
ΔH = m·c·(T₂ - T₁) where ΔH = heat absorbed by the alloy = 956 J, c = specific heat capacity of the alloy and T₁ = Initial temperature of the alloy = 25 °C , T₂ = Final temperature of the alloy = 37 °C and m = mass of the alloy = 45 g
∴ 956 J = 45 × C × (37 - 25) = 540 g·°C×c or
c = 956 J/(540 g·°C) = 1.77 J/(g·°C)
The specific heat capacity of the alloy is 1.77 J/(g·°C)
Answer:
0.0583g
Explanation:
The equation of the reaction is;
2HNO3(aq) + Mg(OH)2(aq) -------> Mg(NO3)2(aq) + 2H2O(l)
From the question, number of moles of HNO3 reacted= concentration × volume
Concentration of HNO3= 0.100 M
Volume of HNO3 = 20.00mL
Number of moles of HNO3= 0.100 × 20/1000
Number of moles of HNO3 = 2×10^-3 moles
From the reaction equation;
2 moles of HNO3 reacts with 1 mole of Mg(OH)2
2×10^-3 moles reacts with 2×10^-3 moles ×1/2 = 1 ×10^-3 moles of Mg(OH)2
But
n= m/M
Where;
n= number of moles of Mg(OH)2
m= mass of Mg(OH)2
M= molar mass of Mg(OH)2
m= n×M
m= 1×10^-3 moles × 58.3 gmol-1
m = 0.0583g
