Answer:
This question begins with something, you should know: molar mass from water is aproximately 18 g/m, so if 18 grams of water are contained in 1 mole, the 40 grams occuped 2.22 moles. As you see, opcion a is the best!
Explanation:
Answer:
12.18 u
Explanation:
The average atomic mass of an element is calculated by taking the weighted average of the atomic masses of its stable isotopes.
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:
102.807 kPa
Explanation:
There are some assumptions to be made in the answer. The air inside the balloon acts as an ideal gas at a given temperature conditions.
Using the combined ideal gas equation.
P= absolute pressure of air inside the balloon.
V= volume of air inside the balloon (6.23 L= 6.23 * 10⁻³ m³)
n= moles of gas(air). (0.250 mol)
R= Universal gas constant ( 8.314 J / mol·K)
T= Temperature in Kelvin
T= 35 + 273.15 = 308.15 K
So, 
P= 102.807 * 10³ Pa
P= 102.807 kPa
Explanation:
I think it is maintaining certain internal condition
