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3 years ago

15

Fires in forests can sometimes be stopped by cutting down trees to make a gap called a for break. Which part of the fire triangl

e does this remove?

1 answer:

Ber [7]3 years ago

5 0

It removes the fuel for the flame.

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Define the following symbols that are encountered in rate equations: [A]0, t1/2 [A]t, k.

dezoksy [38]

[A]0= Initial concentration
t1/2= half life
[A]= final concentration
k= rate constant

5 0

3 years ago

How many molecules are in 3.50 moles of H2O<br>

Debora [2.8K]

Answer:

2.11 x 10²⁴ molecules.

Explanation:

<em>It is known that every 1.0 mole of a molecule contains Avogadro's number of molecules (NA = 6.022 x 10²³).</em>

<em><u>Using cross multiplication:</u></em>

1.0 mole of H₂O contains → 6.022 x 10²³ molecules.

3.5 mole of H₂O contains → ??? molecules.

∴ 3.5 mole of H₂O contain = (3.5 mol)(6.022 x 10²³) = 2.11 x 10²⁴ molecules.

5 0

3 years ago

Who was the first to propose the idea of atoms?

VMariaS [17]

Answer::Democritus

Explanation

The idea that all matter is made up of tiny, indivisible particles, or atoms, is believed to have originated with the Greek philosopher Leucippus of Miletus and his student Democritus of Abdera in the 5th century B.C. (The word atom comes from the Greek word atomos, which means “indivisible.”) These thinkers held that,

5 0

3 years ago

Read 2 more answers

What is the composition, in atom percent, of an alloy that consists of a) 5.5 wt% Pb and b) 94.5 wt% of Sn? Assume that the atom

Anastaziya [24]

Answer : The percent composition of Pb and Sn in atom is, 3.21 % and 96.8 % respectively.

Explanation :

First we have to calculate the number of atoms in 5.5 wt% Pb and 94.5 wt% of Sn.

As, 207.2 g of lead contains $6.022\times 10^{23}$ atoms

So, 5.5 g of lead contains $\frac{5.5}{207.2}\times 6.022\times 10^{23}=1.59\times 10^{22}$ atoms

and,

As, 118.71 g of lead contains $6.022\times 10^{23}$ atoms

So, 94.5 g of lead contains $\frac{94.5}{118.71}\times 6.022\times 10^{23}=4.79\times 10^{23}$ atoms

Now we have to calculate the percent composition of Pb and Sn in atom.

$\% \text{Composition of Pb}=\frac{\text{Atoms of Pb}}{\text{Atoms of Pb}+\text{Atoms of Sn}}\times 100$

$\% \text{Composition of Pb}=\frac{1.59\times 10^{22}}{(1.59\times 10^{22})+(4.79\times 10^{23})}\times 100=3.21\%$

and,

$\% \text{Composition of Sn}=\frac{\text{Atoms of Sn}}{\text{Atoms of Pb}+\text{Atoms of Sn}}\times 100$

$\% \text{Composition of Sn}=\frac{4.79\times 10^{23}}{(1.59\times 10^{22})+(4.79\times 10^{23})}\times 100=96.8\%$

Thus, the percent composition of Pb and Sn in atom is, 3.21 % and 96.8 % respectively.

6 0

3 years ago

What is the formula for tin(IV) sulfide?<br> A. Sn4S<br> B. SnS2<br> C. Sns<br> D. SnS4

defon

Answer:

$SnS_{2}$

Explanation:

The formula for tin(IV) sulfide is SnS $_{2}$

6 0

3 years ago