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3 years ago

Why don’t the trees spontaneously catch fire and burn all the time? Why don’t the fires stop immediately as soon as they start?

Chemistry

1 answer:

algol133 years ago

7 0

Answer:

Both of these phenomena is due to the ignition temperature.

Explanation:

Trees don't spontaneously catch fire because there is a temperature above which materials combust. This is called the "ignition temperature." This temperature must be reached before the trees will ignite, and the external condition does not always harbor such high temperature.

Fires don't stop immediately because, while some parts of the flame has cooled down sufficiently below the ignition temperature, other parts of the flame have not. It takes time for all the part of the flame to cool down below ignition temperature for the burning to stop.

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Which of earth's spheres is most affected by weathering and erosion

Natali [406]

Answer: the hydrosphere

Explanation:

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3 years ago

Los materiales sinteticos tienen implicaciones en el medio ambiente

svp [43]

Answer:

Explanation:

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6 0

2 years ago

How many grams of aluminum are required to react with 35 mL of 2.0 M hydrochloric acid, HCl?__ HCl + __ Al --> __ AlCl3 + __

kiruha [24]

Answer:

0.6258 g

Explanation:

To determine the number grams of aluminum in the above reaction;

determine the number of moles of HCl
determine the mole ratio,
use the mole ratio to calculate the number of moles of aluminum.
use RFM of Aluminum to determine the grams required.

Moles of HCl

35 mL of 2.0 M HCl

2 moles of HCl is contained in 1000 mL

x moles of HCl is contained in 35 mL

$x \: mol \: = \: \frac{2 \: \times \: 35}{1000} \\ = 0.07 \: moles \:$

We have 0.07 moles of HCl.

Mole ratio

Balanced equation

6HCl(aq) + 2Al(s) --> 2AlCl3(aq) + 3H2(g)

Hence mole ratio = 6 : 2 (HCl : Al

but moles of HCl is 0.07, therefore the moles of Al;

$= \frac{2}{6} \times 0.07 \\ \: = 0.0233333 \: moles$

Therefore we have 0.0233333 moles of aluminum.

Grams of Aluminum

We use the formula;

$grams \: = moles \: \times \: rfm$

The RFM (Relative formula mass) of aluminum is 26.982g/mol.

Substitute values into the formula;

$= 0.0233333 \: moles \: \times \: 26.982 \: \frac{g}{mol} \\ = 0.625799 \: grams$

The number of grams of aluminum required to react with HCl is 0.6258 g.

3 0

2 years ago

2) what is the mass of 6.02 x 1023 atoms of arsenic?

zzz [600]

Data:
Arsenic Molar Mass = 74,9216 ≈ 75 u (atomic mass unit)

Solving:

1 mole of arsenic → 75g ------------ 6,02*10²³ molecules
..................................X -------------- 1 molecule

6,02*10²³X = 75
$x = \frac{75}{6,02*10^{23}}$
$\boxed{x \approx 1,24*10^{24}grams}$

6 0

3 years ago

An organic compound is composed of 38.7% C, 9.70% H, 51.6% O. The compound has a molecular formula mass of 62.0g/mol.

Tcecarenko [31]

B)C2H6O2

First, convert each percentage to grams: 38.7g, 9.70g, and 51.6g.
Next, calculate the number of moles of each element, based on the number of grams given.
C = 3.23 mol
H = 8.91 mol
O = 3.23 mol
Set up the ratio of moles of each element:
C3.34H9.70O3.23. Convert the decimals to whole numbers by dividing by the smallest subscript, 3.23.
The empirical formula is CH3O.
Now, compute the formula mass, which is 31. Finally, divide the molecular mass by the formula mass, 62/31 = 2. Multiple the subscripts by 2 to get the molecular formula.

5 0

3 years ago

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