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3 years ago

Which statement best describes a chemical reaction?

Chemistry

1 answer:

ziro4ka [17]3 years ago

7 0

Answer:

In a chemical reaction, one or more substances called reactants are combined or broken down to form products.

Explanation:

Chemical reaction:

In a chemical reaction one or more substance converted into the another substance.

The substances that reacts or combine during the chemical reaction are called reactants while the new species formed as a result of chemical reaction are products.

There are different types of reaction given below:

Decomposition reaction:

It is the reaction in which one reactant is break down into two or more product.

AB → A + B

Synthesis reaction:

It is the reaction in which two or more simple substance react to give one or more complex product.

Single replacement:

It is the reaction in which one elements replace the other element in compound.

AB + C → AC + B

Double replacement:

It is the reaction in which two compound exchange their ions and form new compounds.

AB + CD → AC +BD

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What is the symbol for gold

Slav-nsk [51]

The elemental symbol of gold is denoted on the periodic table as being Au.

5 0

4 years ago

Use the word bank to complete the charts about the metrics system measurement

Aloiza [94]

Answer:

Length

- centimetre

- millimetre

- kilometre

- meter

Mass

- gram

- kilogram

Capacity

- liter

- millilitre

I don't know why mass is there but hope this helps! :)

5 0

3 years ago

How many moles are in 135g of Teflon?

Oliga [24]

1.34 moles are in 135g of Teflon.

Explanation:

Molecular formula of teflon is (C2H4)n

mass of teflon = 135 grams

atomic mass of teflon = 100.01 gram/mole

number of moles of teflon = ?

Formula used to calculate number of moles in a substance is given as:

number of moles = $\frac{mass}{atomic mass of 1 mole}$

putting the values in the above equation:

number of moles = $\frac{135}{100.01}$

number of moles = 1.34 moles

Teflon is polymer which is used for making non-stick coating, in 135 grams of teflon there are 1.34 moles in it.

5 0

3 years ago

Give the name and formula of the compound formed from the following elements: (a) sodium and nitrogen; (b) oxygen and strontium;

lisov135 [29]

Answer:

For a: The chemical name and chemical formula formed is sodium nitride and $Na_3N$

For b: The chemical name and chemical formula formed is strontium oxide and $SrO$

For c: The chemical name and chemical formula formed is aluminium chloride and $AlCl_3$

Explanation:

For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.

The nomenclature of ionic compounds is given by:

1. Positive is written first.

2. The negative ion is written next and a suffix is added at the end of the negative ion. The suffix written is '-ide'.

For a: Sodium and nitrogen:

Sodium is the 11th element of periodic table having electronic configuration of $[Ne]3s^1$

To form $Na^{+}$ ion, this element will loose 1 electron.

Nitrogen is the 7th element of periodic table having electronic configuration of $[He]2s^22p^3$ .

To form $N^{3-}$ ion, this element will gain 3 electrons.

By criss-cross method, the oxidation state of the ions gets exchanged and they form the subscripts of the other ions. This results in the formation of a neutral compound.

So, the chemical formula for sodium nitride is $Na_3N$

For b: Oxygen and strontium

Strontium is the 38th element of periodic table having electronic configuration of $[Kr]5s^2$ .

To form $Sr^{2+}$ ion, this element will loose 2 electrons.

Oxygen is the 8th element of periodic table having electronic configuration of $[He]2s^22p^4$ .

To form $O^{2-}$ ion, this element will gain 2 electrons.

By criss-cross method, the oxidation state of the ions gets exchanged and they form the subscripts of the other ions. This results in the formation of a neutral compound.

So, the chemical formula for strontium oxide is $SrO$

For c: Aluminium and chlorine

Aluminium is the 13th element of periodic table having electronic configuration of $[Ne]3s^23p^1$

To form $Al^{3+}$ ion, this element will loose 3 electrons.

Chlorine is the 17th element of the periodic table having electronic configuration of $[Ne]3s^23p^5$

To form $Cl^{-}$ ion, this element will gain 1 electron.

By criss-cross method, the oxidation state of the ions gets exchanged and they form the subscripts of the other ions. This results in the formation of a neutral compound.

So, the chemical formula for aluminium chloride is $AlCl_3$

4 0

4 years ago

Do Alkali Metal Compounds form precipitates? And Why?

Alexeev081 [22]

Answer:

Alkali metal hydroxides can be used to test the identity of metals in certain salts. The colour of the precipitate will help identify the metal : Calcium hydroxide is soluble; no precipitate is formed.

6 0

2 years ago