If the dots are going to the right, it's positive. If they're going to the left, they're negative.
Answer:
- 0.71963 g of Zn
- 0.80256 g of HCl
Step-by-step explanation:
The required mass of reactants can be computed from the number of moles of product.
moles of ZnCl₂ = (1.5 g)/(136.282 g) ≈ 0.0110066 moles
Then the mass of Zn required is ...
mass of Zn = (0.0110066 mol)(65.382 g/mol) = 0.71963 g
Two moles of HCl are used in the reaction with each mole of Zn, so the mass of HCl required is ...
mass of HCl = 2(0.0110066 mol)(36.458 g/mol) = 0.80256 g
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<em>Comment</em>
The discrepancy in the last two decimal places of the weights above versus the calculator output below comes from rounding of moles of Zn to 4 significant digits, instead of 5 or more. The number of moles of ZnCl₂ is closer to 0.0110066.
De Moivre's theorem uses this general formula z = r(cos α + i<span> sin α) that is where we can have the form a + bi. If the given is raised to a certain number, then the r is raised to the same number while the angles are being multiplied by that number.
For 1) </span>[3cos(27))+isin(27)]^5 we first apply the concept I mentioned above where it becomes
[3^5cos(27*5))+isin(27*5)] and then after simplifying we get, [243 (cos (135) + isin (135))]
it is then further simplified to 243 (-1/ √2) + 243i (1/√2) = -243/√2 + 243/<span>√2 i
and that is the answer.
For 2) </span>[2(cos(40))+isin(40)]^6, we apply the same steps in 1)
[2^6(cos(40*6))+isin(40*6)],
[64(cos(240))+isin(240)] = 64 (-1/2) + 64i (-√3 /2)
And the answer is -32 -32 √3 i
Summary:
1) -243/√2 + 243/√2 i
2)-32 -32 √3 i
14 / 3.5 = 4.....4 tablets should be administered
Answer:
It will take 100 songs for the monthly price of Napster to cost the same as iTunes.
Step-by-step explanation:
Let's create two equations to represent iTunes (T(d)) and Napster (N(d)):
T(d)=0.99d
N(d)=0.89d+10
In order for us to find when the two prices will be the same, let's set the equations equal to each other and solve for x:
0.99d=0.89d+10
0.1d=10
d=100