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3 years ago

A log burns to ashes in a fireplace what kind of change is this

Chemistry

2 answers:

FrozenT [24]3 years ago

6 0

Answer:

Chemical Change

Explanation:

Burning of wood is a chemical change as new substances which cannot be changed back [e.g. carbon dioxide] are formed. For example, if wood is burned in a fireplace, there is not wood anymore but ash.

KengaRu [80]3 years ago

3 0

Answer:

A log burning to ashes is a chemical change.

Explanation:

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Is snails growing shell conserve mass

postnew [5]

The thing that two changes have in common that snails growing shells and rust forming on a bicycle frame is option D. Both are caused by cooling.

<h3>How come snails develop shells?</h3>

Calcium carbonate is said to be the material that makes up the shell. The snail's shell expands as it grows to accommodate its growing body. Snails and slugs are also members of the mollusc family of creatures.

Therefore, note that air that has been mixed with the metal can make rust to develop. and as such, option D. Both are caused by cooling. is correct.

Learn more about snails growing shells from
brainly.com/question/15758489

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See full question below

What do these two changes have in common? snails growing shells rust forming on a bicycle frame Select all that apply.

A. Both are only physical changes.

B. Both are caused by heating.

C. Both are chemical changes.

D. Both are caused by cooling

5 0

1 year ago

What information does the atominic numer give you about an element

uysha [10]

Answer:

It gives the number of protons in the nucleus of each atom of that element.

Explanation:

6 0

2 years ago

Chlorine has two naturally stable isotopes: 35Cl (34.968853 amu) and 37Cl (36.965903 amu). The natural abundance of each isotope

allochka39001 [22]

Answer:

35Cl ⇒ 34.968853 amu has an abundance of 30.05%

Explanation:

The molar mass of chlorine, (which is the average of all its naturally stable isotope masses), is 36.36575 amu.

There are 2 naturally stable isotopes, this means together they have an abundance of 100%

The isotopes are:

35Cl ⇒ 34.968853 amu has an abundance of X %

37Cl ⇒ 36.965903 amu has an abundance of Y %

X + Y = 100% OR X = 100% - Y

36.36575 = 34.968853X + 36.965903Y

36.36575 = 34.968853(1-Y) + 36.936.96590365903Y

36.36575 = 34.968853 -34.968853Y + 36.965903Y

1.396897 = 1.99705Y

Y = 0.699 = 69.95%

X = 100-69.9 = 30.05%

To control, we can plug in the following equation:

34.968853 * 0.3005 + 36.965903 * 0.6995 = 36.3658

This means

37Cl ⇒ 36.965903 amu has an abundance of 69.95 %

35Cl ⇒ 34.968853 amu has an abundance of 30.05%

7 0

3 years ago

How many grams of copper (II) hydroxide can be prepared from 2.4 grams of copper (II) nitrate (Cu(NO3)2 ) and excess sodium hydr

andreyandreev [35.5K]

Answer:

percentage yield = 67%

Explanation:

Mass of Cu(NO₃)₂ = 15.25 g

Mass of NaOH = 12.75 g

Percentage yield = ?

Solution:

Cu(NO₃)₂ + 2NaOH → Cu(OH)₂ + 2NaNO₃

Moles of Cu(NO₃)₂:

Number of moles = mass/ molar mass

Number of moles = 15.25 g /187.56 g/mol

Number of moles = 0.08 mol

Moles of NaOH :

Number of moles = mass/ molar mass

Number of moles = 12.75 g / 40 g/mol

Number of moles = 0.32 mol

Now we will compare the moles of Cu(OH)₂ with NaOH and Cu(NO₃)₂. NaOH : Cu(OH)₂

2 : 1

0.32 : 1/2×0.32 = 0.16 mol

Cu(NO₃)₂ : Cu(OH)₂

1 : 1

0.08 : 0.08

The number of moles produced by Cu(NO₃)₂ are less so it will limiting reactant.

Mass of Cu(OH)₂:

Mass = number of moles × molar mass

Mass = 0.08 mol × 97.6 g/mol

Mass = 7.808 g

Theoretical yield = 7.808 g

Percent yield:

percentage yield = Actual yield/ theoretical yield × 100

percentage yield = 5.23 g/ 7.808 g × 100

percentage yield = 0.67 × 100

percentage yield = 67%

5 0

2 years ago

An ideal gas is contained in a cylinder with a volume of 5.0x102 mL at a temperature of 30°C and a pressure of 710. Torr. The ga

Scorpion4ik [409]

Answer:

51207 torr is the new pressure of the gas

Explanation:

We can solve this question using combined gas law that states:

P1V1T2 = P2V2T1

<em>Where P is pressure, V volume and T absolute temperature of 1, initial state and 2, final state of the gas</em>

Computing the values of the problem:

P1 = 710torr

V1 = 5.0x10²mL

T1 = 273.15 + 30°C = 303.15K

P2 = ?

V2 = 25mL

T2 = 273.15 + 820°C = 1093.15K

Replacing:

710torr*5.0x10²mL*1093.15K = P2*25mL*303.15K

3.881x10⁸torr*mL*K = P2 * 7.579x10³mL*K

P2 = 51207 torr is the new pressure of the gas

4 0

2 years ago

A log burns to ashes in a fireplace what kind of change is this​

A log burns to ashes in a fireplace what kind of change is this