Answer:
mass and volume are independent. Two objects with the same volume can have different masses hence they can have different densities
Explanation:
The mass of atoms their size and how they are arranged determine the density
Answer:
2-0-1, 1-1-1, 0-1-2, but they must all equal 3 electrons in total
Explanation:
Carbon, Nitrogen, and Oxygen all have the same number of energy levels because periods (rows) tell the amount of energy levels an element has.
Answer:
311.25k
Explanation:
The question assumes heat is not lost to the surroundings, therefore
heat emitted from hotter sample (
)= heat absorbed by the less hotter sample(
)
The relationship between heat (q), mass (m) and temperature (t) is 
where c is specific heat capacity,
temperature change.
= 
equating both heat emitted and absorb


where the values with subset 1 are the values of the hotter sample of water and the values with subset 2 are the values of the less hot sample of water.
C will cancel out since both are water and they have the same specific heat capacity.
so we have

where m1 = 50g, t 1initial = 330, m2 = 30g, t2 initial = 280,t final (final temperature of the mixture) = ?
-50 * (
- 330) = 30 * (
- 280)
-50
+ 16500 = 30
- 8400
80
= 16500+8400
80
= 24900
= 24900/80 = 311.25k
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>