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3 years ago

Explain why burning is a chemical change in wood

2 answers:

5 0

The carbon element in wood reacts to the oxygen so it creates, energy as we all know as light and heat, ashes, and smoke. Hope this helps!

Leto [7]3 years ago

4 0

It is a chemical change in wood because a chemical change is when some object is being changed. So when fire burns on wood it changes how the wood is. The wood goes from whole to ash dust. Hope I could help. ;-)

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Grease is applied to the moving part of machine.

RideAnS [48]

Answer:

Explanation:

The moving part won't move on its own there's a force but the force isn't enough for something like a bike chain it need grease to move smoothly or else it will just be super stuck or slow.

6 0

3 years ago

Read 2 more answers

Given 4.80g of ammonium carbonate, find:

V125BC [204]

Answer:

1) 0.05 mol.

2) 0.1 mol.

3) 0.05 mol.

4) 0.4 mol.

5) 2.4 x 10²³ molecules.

Explanation:

1) Number of moles of the compound:

no. of moles of ammonium carbonate = mass/molar mass = (4.80 g)/(96.09 g/mol) = 0.05 mol.

2) Number of moles of ammonium ions :

Ammonium carbonate is dissociated according to the balanced equation:

(NH₄)₂CO₃ → 2NH₄⁺ + CO₃²⁻.

It is clear that every 1.0 mole of (NH₄)₂CO₃ is dissociated to produce 2.0 moles of NH₄⁺ ions and 1.0 mole of CO₃²⁻ ions.

∴ The no. of moles of NH₄⁺ ions in 0.05 mol of (NH₄)₂CO₃ = (2.0)(0.05 mol) = 0.1 mol.

3) Number of moles of carbonate ions :

Ammonium carbonate is dissociated according to the balanced equation:

(NH₄)₂CO₃ → 2NH₄⁺ + CO₃²⁻.

It is clear that every 1.0 mole of (NH₄)₂CO₃ is dissociated to produce 2.0 moles of NH₄⁺ ions and 1.0 mole of CO₃²⁻ ions.

∴ The no. of moles of CO₃²⁻ ions in 0.05 mol of (NH₄)₂CO₃ = (1.0)(0.05 mol) = 0.05 mol.

4) Number of moles of hydrogen atoms:

Every 1.0 mol of (NH₄)₂CO₃ contains:

2.0 moles of N atoms, 8.0 moles of H atoms, 1.0 mole of C atoms, and 3.0 moles of O atoms.

∴ The no. of moles of H atoms in 0.05 mol of (NH₄)₂CO₃ = (8.0)(0.05 mol) = 0.4 mol.

5) Number of hydrogen atoms:

It is known that every mole of a molecule or element contains Avogadro's number (6.022 x 10²³) of molecules or atoms.

Using cross multiplication:

1.0 mole of H atoms contains → 6.022 x 10²³ atoms.

0.4 mole of H atoms contains → ??? atoms.

∴ The no. of atoms in 0.4 mol of H atoms = (6.022 x 10²³ molecules)(0.4 mole)/(1.0 mole) = 2.4 x 10²³ molecules.

8 0

3 years ago

How many atoms are in 5.76 moles of aluminum?

mariarad [96]

Answer:The number of atoms in 2.0 mole Al is A. 2.0 Al atoms. B. 3.0 x 1023 Al atoms.

Secondly, is aluminum an atom or molecule? Aluminum is the second element in the thirteenth column of the periodic table. It is classified as a post-transition metal and a "poor metal". Aluminum atoms contain 13 electrons and 13 protons. There are 3 valence electrons in the outer shell.

7 0

3 years ago

What will the pressure be if 89.9 moles of argon are contained in a 12.0 L cylinder that is pressurized at a temperature of 300

irinina [24]

P=nRT/V
p=89.9(8.314)(12)/300
P=8969.14/300
P=29.89atm
P=29.9atm

Done!

7 0

2 years ago

The prefix ‘kilo-‘ means a thousand.

Blababa [14]

Answer:

0.97 kg, 1.0kg

Explanation:

As you have mentioned in the question, to convert kilo-gram to grams, this conversion is used, 1 kilogram = 1,000 grams

Initially, when one has to convert from one unit to another, there is a lot of confusion. To avoid any such, multiply and divide the number with units to which it has to be converted.

Here,

970 g = $970 g \times\frac{1 kg}{1 kg}$

This makes no difference to the number.

970 g = $970 g \times\frac{1 kg}{1000 g}$

As, 1 kg= 1,000 g

970 g = $\frac{970}{1000} kg$

970 g = 0.97 kg

Rounding this off to the nearest tenth of a kilogram.

The tenths place is immediately to the right of the decimal point.

Here, 9 is at the tenth's place. Round the tenth's place up if the digit at hundredth's place is greater than or equal to 5. Since, 7 > 5, up the number at tenth's place.

So, answer is 1.0 kg

8 0

3 years ago