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Andrej [43]
3 years ago
7

(Can someone please help me...im literally done with brainly...) Which answer best completes the following sentence? _____ is an

example of physical change while _____ is an example of a chemical change. (1 point) Freezing water, boiling nitrogen Breaking a pencil, rusting of iron Burning wood, dissolving salt in water Bending a piece of aluminum, condensing water vapor
Chemistry
1 answer:
Furkat [3]3 years ago
5 0

Answer:

(1) breaking a pencil (2) rusting of iron

Explanation:

breaking a pencil does not alter the chemical properties of the pencil, it merely breaks it into 2 while the rusting of iron is changing the properties chemically because the iron is oxidizing and reacting with the water and oxygen in the atmosphere

You might be interested in
Why does every sample of water have the same boiling point?
Tamiku [17]

Answer:

beacuse water is same every where because it is the combination of h2 +o2 h2o which doesn't change while it is different

Explanation:

ok

8 0
3 years ago
Which term represents the fixed proportion of elements in a compound
Gekata [30.6K]

Answer:

Chemical formula.

Explanation:

A chemical formula have fix proportion of atoms of elements.

Chemical formula:

A chemical formula is the way of presenting the chemical proportion of atoms of those elements, that combine to form a compound.

For example:

Water consist of two atom of hydrogen and one atom of oxygen. The atoms of both elements combine to form a compound i.e water. The atoms of both elements always combine in a fixed ratio which is 2:1 in molecule of water.

H₂O

2:1

Carbon dioxide consist of two atom of oxygen and one atom of carbon. The atoms of both elements combine to form a compound i.e carbon dioxide. The atoms of both elements always combine in a fixed ratio which is 1:2 in molecule of carbon dioxide .

CO₂

1;2

5 0
3 years ago
An important reaction that takes place in a blast furnace during the production of iron is the formation of iron metal and CO2 f
ladessa [460]

Answer: Mass of Fe_2O_3 required to form 930 kg of iron is 1328 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 iron:

Given mass of iron = 930 kg = 930000 g  (1kg=1000g)

Molar mass of iron = 56 g/mol

Putting values in equation 1, we get:

\text{Moles of iron}=\frac{930000g}{56g/mol}=16607mol

The chemical equation for the  production of iron  follows:

Fe_2O_3+3CO\rightarrow 2Fe+3CO_2

By Stoichiometry of the reaction:

2 moles of iron are  produced by =  1 mole of Fe_2O_3

So, 16607 moles of iron will be produced by = \frac{1}{2}\times 16607=8303moles of Fe_2O_3

Now, calculating the mass of Fe_2O_3 from equation 1, we get:

Mass of Fe_2O_3 = moles\times {\text {molar mass}}=8303\times 160=1328480g=1328kg

Thus mass of Fe_2O_3 required to form 930 kg of iron is 1328 kg

6 0
3 years ago
The is the si unit that expresses the amount of substance. Specifically, it is defined as the amount of substance containing the
Dmitry_Shevchenko [17]

The <u>Mole</u> is the SI unit that expresses the amount of substance.

Mole is defined as - The mole is the amount of substance containing the same number of entities as there are in the 12 grams of Carbon - 12.

Mole is denoted by using symbol mol.

      Mole = 6.022 x 10²³ elementary entities.

These number of elementary entities in 1 mole is equal to or called as an Avogadro's number.  Mole is equal to 6.022 x 10²³ because this number of entity is same as in exactly 12 g of carbon-12.

It is a very important SI unit of measured which is used by the chemists. Moles are used in measuring in small or tiny things such as atoms, molecules and the other tiny particles.

To learn more about the mole concept,

brainly.com/question/28498715

#SPJ4

3 0
1 year ago
When 120 g of carbon reacts completely with 320 g of oxygen the mass of carbon dioxide formed will be?
olga2289 [7]
440 cause mass cant be created or destroyed
6 0
3 years ago
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