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3 years ago

What properties do all chemical reactions have in common?

Chemistry

2 answers:

sp2606 [1]3 years ago

5 0

Answer. The common properties of chemical reactions are:

Temperature: Change in temperature will be there. This change can be increase in temperature (exothermic) or decrease in temperature (endothermic).

Formation of product: The product will be formed if the chemical reaction has taken place. Product formed can be in any state (solid, liquid or gas). This formation of product can be observed by looking out for change in color, change in odour or substance getting disappeared.

Number of products: Minimum number of products formed after chemical reaction is one. More than one number of products can be formed.

kati45 [8]3 years ago

4 0

What all chemical reactions have in common is that energy is released in various forms. Sometimes it's heat or light when there's an explosion, or theres gas and odors or a change in color, or sometimes solids are formed as a deposit. This all show that a reaction occurred and are used as proof.

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Find the hydroxide ion concentration of a HBr solution with a pH of 4.75

Sunny_sXe [5.5K]

1st find the pOH = 14 - 4.75 = 9.25
then do 10^-9.25 = 5.62x10^-10 OH- concentration

8 0

4 years ago

What is one way scientists can split a substance into its simpler components

notsponge [240]

Answer: By using electrolysis.

Explanation:

Electrolysis is a chemical change produced by sending an electric current through a compound. Electrolysis works because the hydrogen and oxygen ions are held together by an electric attraction.

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3 years ago

Cryolite, Na3AlF6(s), an ore used in the production of aluminum, can be synthesized using aluminum oxide. Balance the equation f

dmitriy555 [2]

Answer: The mass of cryolite produced is 51.48 kg

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

For aluminium oxide:

Given mass of aluminium oxide = 12.5 kg = 12500 g (Conversion factor: 1 kg = 1000 g)

Molar mass of aluminium oxide = 101.96 g/mol

Putting values in equation 1, we get:

$\text{Moles of aluminium oxide}=\frac{12500g}{101.96g/mol}=122.6mol$

For NaOH:

Given mass of NaOH = 55.4 kg = 55400 g

Molar mass of NaOH = 40 g/mol

Putting values in equation 1, we get:

$\text{Moles of NaOH}=\frac{55400g}{40g/mol}=1389mol$

For HF:

Given mass of HF = 55.4 kg = 55400 g

Molar mass of HF = 20 g/mol

Putting values in equation 1, we get:

$\text{Moles of HF}=\frac{55400g}{20g/mol}=2770mol$

For the given chemical reaction:

$Al_2O_3(s)+6NaOH(l)+12HF(g)\rightarrow 2Na_3AlF_6+9H_2O(g)$

By Stoichiometry of the reaction:

1 mole of aluminium oxide reacts with 6 moles of sodium hydroxide and 12 moles of HF.

So, 122.6 moles of aluminium oxide will react with $(6\times 122.6)=735.6mol$ of sodium hydroxide and $(12\times 122.6)=1471.2mol$ of HF

As, given amount of NaOH and HF is more than the required amount. So, they are considered as an excess reagent.

Thus, aluminium oxide is considered as a limiting reagent because it limits the formation of product.

By Stoichiometry of the reaction:

1 mole of aluminium oxide produces 2 moles of cryolite

So, 122.6 moles of aluminium oxide will produce = $\frac{2}{1}\times 122.6=245.2mol$ of cryolite

Now, calculating the mass of cryolite by using equation 1:

Molar mass of cryolite = 209.94 g/mol

Moles of cryolite = 245.2 mol

Putting values in equation 1, we get:

$245.2mol=\frac{\text{Mass of cryolite}}{209.94g/mol}\\\\\text{Mass of cryolite}=(245.2mol\times 209.94g/mol)=51477.3g$

Converting this into kilograms, we use the conversion factor:

1 kg = 1000 g

So, $51477.3 g\times (\frac{1kg}{1000g})=51.48kg$

Hence, the mass of cryolite produced is 51.48 kg

7 0

3 years ago

Which type of matter can be separated by physical means? A. atom B. element C. compound D. mixture

madreJ [45]

Answer:

Explanation:

A pure substance has a constant composition and cannot be separated into simpler substances by physical means. There are two types of pure substances: elements and compounds.

7 0

3 years ago

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Which of these is an indication that a chemical reaction has occurred?

Kobotan [32]

Answer:

The correct option is C.
Formation of a precipitate

Explanation:

During a chemical reaction, new substances are formed known as a products, mostly reaction occur and their product is obtained as precipitates.

Example

Arylidene-2-thiobarbituric acid is obtained as precipitates when aldehyde and thiobarbituric acid react to each other.

melting of a substance

It is just indication of physical changes, like melting of ice, composition remained same as before.

boiling of a substance

It is just indication of physical changes, like boiling of water into vapors, composition remained same as before.

freezing of a substance

It is just indication of physical changes, like freezing of water into ice, composition remained same as before

7 0

3 years ago

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