Here's how to do it:
<span>Balanced equation first: </span>
<span>Mg + HCl = H2 + MgCl2 unbalanced </span>
<span>Mg + 2 HCl = H2 = MgCl balanced </span>
<span>Therefore 1 mole Mg reacts with 2 moles Hcl. </span>
<span>50g Mg = ? moles (a bit over 2; you work it out) </span>
<span>75 g HCl = ? moles (also a bit over 2; you work it out) </span>
<span>BUT, you need twice the moles HCl; therefore it is the Mg that is in excess. (you can now work out how many moles are in excess, and therefore how much mg is left over). </span>
<span>So, 2 moles HCl produce 1 mole H2(g) </span>
<span>therefore, the amount of H2 produced is half the number of moles of HCl </span>
<span>At STP, there are X litres per mole of gas (look it up - about 22 from memory) </span>
<span>Therefore, knowing the moles of H2, you can calculate the volume</span>
Answer:
Since HCl is a strong acid, it completely ionizes, and the pH of HCl in solution can be found from the concentration (molarity) of the H+ ions, by definition equal to 0.100 M. (The conjugate base of the acid, which is the chloride ion Cl–, would also have a concentration of 0.100 M.) The pH is thus –log(0.100) = 1.000.
Explanation:
<h3>
Answer:</h3>
0.387 J/g°C
<h3>
Explanation:</h3>
- To calculate the amount of heat absorbed or released by a substance we need to know its mass, change in temperature and its specific heat capacity.
- Then to get quantity of heat absorbed or lost we multiply mass by specific heat capacity and change in temperature.
- That is, Q = mcΔT
in our question we are given;
Mass of copper, m as 95.4 g
Initial temperature = 25 °C
Final temperature = 48 °C
Thus, change in temperature, ΔT = 23°C
Quantity of heat absorbed, Q as 849 J
We are required to calculate the specific heat capacity of copper
Rearranging the formula we get
c = Q ÷ mΔT
Therefore,
Specific heat capacity, c = 849 J ÷ (95.4 g × 23°C)
= 0.3869 J/g°C
= 0.387 J/g°C
Therefore, the specific heat capacity of copper is 0.387 J/g°C
You would need exactly 50 molecules of glucose.
A helium balloon displaces the amount of air. The weight of the helium in the balloon + the balloon fabric = lighter than the air that it displaces. Helium is lighter than air, so therefore, if it's in a balloon, the balloon will float.
