Burning wood is a chemical change and not a physical change because the carbon reacts with the oxygen, and that creates ash and smoke, you cannot undo ash and smoke, so therefore, it's only a chemical change
Answer:
0.052636002587839 moles
Explanation:
im not sure so sorry if u get it wrong...
Q1. The answer is 3 minutes.
Let's first calculate the remaining amount in percent:
If 960g is 100 percent (starting amount), 30 g is how many percents:
960 g : 100% = 30 g : x
x = 30 g * 100% / 960 g = 3.125% = 0.03125
Now, using the formula to calculate the number of half-lives:
(1/2)ⁿ = x,
where
x is the remaining amount: x = 0.03125
n is the number of half-lives
1/2 stands for half-life.
(1/2)ⁿ = 0.03125
⇒ n*log(1/2) = log(0.03125)
n = log(0.03125)/log(1/2) = log(0.03125)/log(0.5) = -1.505/-0.301 ≈ 5
The number of half-lives is 5.
Now, <span>the number of half-lives (n) is a quotient of total time elapsed (T) and length of half-life (L):
n = T/L
We know:
n = 5
T = 15 min
L = ?
Thus
L = T/n
L = 15 min/5 = 3 minutes
Q2. Filtration should be chosen.
Filtration and distillation are used to separate mixtures - filtration for the separation of heterogeneous mixtures and </span>distillation for the separation of homogeneous mixtures. Imagine that your pile of soil is a mixture. It consists of different components (the leaves, acorns, twigs), so it is the heterogeneous mixture. Therefore, to separate the leaves, acorns, twigs you will use filtration.
<span>Alkyl is a rare compound, and also very confusing.
I'm assuming you meant "propane"...
</span>
<span><span><span>C3H<span>8 = Propane
</span></span>CnH2n+1--
X</span> << Alkyl Halide
X = Cl
Simply set a chemical reaction :
</span>
<span>C3H<span>8 → </span></span><span>CnH2n+1--
X </span>
<u>Answer: </u>The correct answer is Option A.
<u>Explanation:</u>
The molecule given in the question is HCl which forms a polar covalent bond.
A polar bond is defined as the bond present between two elements with different electronegativity value. The element which has higher electronegativity value, attracts the shared pair of electrons towards itself and forms a dipole. A polar molecule is dissolved more in a polar substance than in non-polar substance.
In the given compound, the electronegativity of chlorine is more than hydrogen and attracts the shared pair of electron more towards itself and hence is a polar molecule.
A non-polar bond is defined as the bond which is formed between the elements having same electronegativity value. No dipole is created in these type of bonds. Here, the electrons are shared equally.
From the above information, the correct answer is Option A.
