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3 years ago

Which process is an example of a chemical change?

Chemistry

2 answers:

WARRIOR [948]3 years ago

8 0

Answer:

A is the closest thing. You change the composition of the steak. You don't in any of the others.

Explanation:

Usually when you cook something, you are doing something to the composition of the object being cooked. A steak might not be obvious, but boiling an egg should be.

Chopping a tree is something physical. You are removing mass in such a way that the tree will fall. There's nothing chemical about that.

Heating a cup of tea looks like it might be chemical. After all steam is sometimes given off which looks like it is chemical. It's not. The water in the tea is just changing phase.

Drying clothes in a dryer. Again, this looks like something might have changed. After all the mass of the clothes just became less. But all you are doing is separating two masses (leaving one of them behind).

aksik [14]3 years ago

6 0

A Sounds like the most relevant one

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The halogens, the elements of Family 17 on the periodic table, combine easily with elements from Family 1. When a halogen reacts

timofeeve [1]

Answer:

When halogen elements react with group one metals they form halide salts.

Explanation:

The elements of group 17 are called halogens. These are six elements Fluorine, Chlorine, Bromine, Iodine, Astatine. Halogens are very reactive these elements can not be found free in nature. Their chemical properties are resemble greatly with each other. As we move down the group in periodic table size of halogens increases that's way fluorine is smaller in size as compared to other halogens elements. Their boiling points also increases down the group which changes their physical states. i.e fluorine is gas while iodine is solid.

When halogen elements react with group one metals they form halide salts.

Alkali metals have one valance electron and halogens needed one electron to complete the octet thus alkali metals loses one electron which is accepted by halogens atom and form ionic compound called halide salts.

For example:

2Na + Cl₂ → 2NaCl

2K + Cl₂ → 2KCl

2Rb + Cl₂ → 2RbCl

2Li + Cl₂ → 2LiCl

With bromine:

2Na + Br₂ → 2NaBr

2K + Br₂ → 2KBr

2Rb + Br₂ → 2RbBr

2Li + Br₂ → 2LiBr

With iodine:

2Na + I₂ → 2NaI

2K + I₂ → 2KBI

2Rb + I₂ → 2RbI

2Li + I₂ → 2LiI

4 0

3 years ago

Convert 5,500 mg to kg. Show your work to receive full credit.

Ivanshal [37]

5500 mg = 0.0055 kg. is the answer

7 0

3 years ago

Copper has two naturally occurring isotopes, 63Cu Gsotopic mass 629396 arnu) and 65Cu Osotopic mass 64.9278 amu). If copper has

madam [21]

Answer: The percentage abundance of $_{29}^{63}\textrm{Cu}$ and $_{29}^{65}\textrm{Cu}$ isotopes are 75.77% and 24.23% respectively

Explanation:

Average atomic mass of an element is defined as the sum of masses of each isotope each multiplied by their natural fractional abundance.

Formula used to calculate average atomic mass follows:

$\text{Average atomic mass }=\sum_{i=1}^n\text{(Atomic mass of an isotopes)}_i\times \text{(Fractional abundance})_i$ .....(1)

Let the fractional abundance of $_{29}^{63}\textrm{Cu}$ isotope be 'x'. So, fractional abundance of $_{29}^{63}\textrm{Cu}$ isotope will be '1 - x'

For $_{29}^{63}\textrm{Cu}$ isotope:

Mass of $_{29}^{63}\textrm{Cu}$ isotope = 62.9396 amu

Fractional abundance of $_{29}^{63}\textrm{Cu}$ isotope = x

For $_{29}^{65}\textrm{Cu}$ isotope:

Mass of $_{29}^{65}\textrm{Cu}$ isotope = 64.9278 amu

Fractional abundance of $_{29}^{65}\textrm{Cu}$ isotope = 1 - x

Average atomic mass of copper = 63.546 amu

Putting values in equation 1, we get:

$63.546=[(62.9396\times x)+(64.9278\times (1-x))]\\\\x=0.6950$

Percentage abundance of $_{29}^{63}\textrm{Cu}$ isotope = $0.6950\times 100=69.50\%$

Percentage abundance of $_{29}^{65}\textrm{Cu}$ isotope = $(1-0.6950)=0.305\times 100=30.50\%$

Hence, the percentage abundance of $_{29}^{63}\textrm{Cu}$ and $_{29}^{65}\textrm{Cu}$ isotopes are 69.50% and 30.50% respectively.

4 0

3 years ago

How many moles are in 4.3 x 10 ^22 molecules of Na3PO4

Sever21 [200]

Answer:

0.071 moles of Na₃PO₄ .

Explanation:

Given data:

Number of molecules of Na₃PO₄ = 4.3× 10²² molecules

Number of moles = ?

Solution:

1 mole contain 6.022 × 10²³ molecules

4.3× 10²² molecules × 1 mol / 6.022 × 10²³ molecules

0.71× 10⁻¹ mol

0.071 mol

The number 6.022 × 10²³ is called Avogadro number.

"It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance"

3 0

3 years ago

Porrrrrrrrrfffffffiiiiiiissssss

Lunna [17]

la viscosidad en la 2.5

la primera en la 2. 6

3 0

3 years ago