Answer:
B - What we change
Explanation:
Dependent Variable - What we measure
Control Variable - what stays the same
Conclusion - what we conclude
<em>Hope</em><em> </em><em>this</em><em> </em><em>can</em><em> </em><em>Help</em><em>!</em>
<em>:</em><em>D</em>
1 mole --------------------------- 6.02 x 10²³ molecules
( moles lithium ) --------------- 1.2 x 10²¹ molecules
( moles lithium ) = (1.2 x 10²¹ ) x 1 / ( 6.02 x 10²³ )
= 1.2 x 10²¹ / 6.02 x 10²³
= 2.0 x 10⁻³ moles of lithium
Answer D
hope this helps!
Hydrogen - 7.44%
Carbon - (100-7.44)% = 92.56%
Lets take 100 g of benzene, then we have
Hydrogen - 7.44 g
Carbon - 92.56 g
n - number of moles
n(H) = 7.44g *1 mol/1.0g = 7.44 mol
n(C) = 92.56 g* 1mol/12.0 g ≈ 7.713 mol
n(C) : n(H) = 7.713 mol : 7.44 mol = 1:1
Empirical formula is CH.
M(CH) = (12.0+ 1.00) g/mol = 13.0 g/mol
M (benzene) = 78.1 g/mol
M (benzene)/M(CH)= 78.1 g/mol/13.0 g/mol = 6
So, molecular formula of benzene is C6H6.
Answer:
No. of moles = 0.0685
Explanation:
Given mass, m = 15.5g
We need to find the number of moles in 15.5 g of CaSO₄.5H2O
First, we find the mass of CaSO₄.5H2O.
M = (1×40)+(1×32)+(4×16)+(5×18)
M = 226 g/mol
We know that,
Number of moles = given mass/molar mass
Hence, there are 0.0685 moles in 15.5 g of CaSO₄.5H2O.
C. Decomposition is a chemical change and melting is a physical change.
