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3 years ago

How many protons, neutrons, and electrons are present in an atom of hafnium, Hf, with a mass number of 178?

1 answer:

6 0

Answer:Hafnium is a chemical element with atomic number 72 which means there are 72 protons and 72 electrons in the atomic structure. The chemical symbol for Hafnium is Hf. Neutron Number and Mass Number of Hafnium Mass numbers of typical isotopes of Hafnium are 176-178, 179, 180.

Explanation:

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True or False Liquids can be easily poured because liquid molecules can roll or slide over each other.

kodGreya [7K]

Answer:

True

Explanation:

4 0

2 years ago

PLEASE HELP! (IM GIVING BRAINLIEST) Iron is a transition metal and, as such, can form two types of "oxide" salt compounds, FeO a

belka [17]

Answer:

See explanation

Explanation:

Iron exhibits two stable oxidation states, +2 and +3 states. The difference between FeO and Fe2O3 is that, in FeO, Fe is in the +2 oxidation state while in Fe2O3, Fe is in the +3 oxidation state

In FeO, iron looses two electrons which are gained by oxygen as follows;

Fe^2+ + O^2- -----> FeO

In Fe2O3, Fe looses six electrons while oxygen has gained six electrons as shown;

2Fe^3+ + 3O^2- ------>Fe2O3

7 0

2 years ago

Which equation represents a conservation of atoms? Group of answer choices LaTeX: 4Fe\:+3O_2\:\longrightarrow\:2Fe_2O_3 4 F e +

slamgirl [31]

Answer : The equation represents a conservation of atoms is:

$4Fe+3O_2\rightarrow 2Fe_2O_3$

Explanation :

Law of conservation of matter : It states that matter can neither be created nor be destroyed but it can only be transformed from one form to another form.

The balanced chemical reaction always follow the law of conservation of matter.

Balanced chemical reaction : It is defined as the reaction in which the number of atoms of individual elements present on reactant side must be equal to the product side.

(1) The given chemical reaction is,

$4Fe+3O_2\rightarrow 2Fe_2O_3$

This reaction is a balanced chemical reaction in which number of atoms of iron and oxygen are equal on the both side of the reaction. So, this reaction obey the law of conservation of matter.

(2) The given chemical reaction is,

$2Fe+2O_2\rightarrow 2Fe_2O_3$

This reaction is an unbalanced chemical reaction in which number of atoms of iron and oxygen are not equal on the both side of the reaction. So, this reaction does not obey the law of conservation of matter.

(3) The given chemical reaction is,

$4Fe+2O_2\rightarrow 2Fe_2O_3$

This reaction is an unbalanced chemical reaction in which number of atoms of oxygen are not equal on the both side of the reaction. So, this reaction does not obey the law of conservation of matter.

Hence, the equation represents a conservation of atoms is:

$4Fe+3O_2\rightarrow 2Fe_2O_3$

3 0

3 years ago

Who was the first U.S. secretary of state to ever visit the remote cook islands in the south pacific

pogonyaev

Answer:

I think it was Hillary Clinton.

Explanation:

6 0

3 years ago

1 C3H8 + 5 O2 --> 3 CO2 + 4H20. If 1.5 moles of C3H8 react, how many

UNO [17]

Answer:

First confirm the reaction is balanced:

C3H8 + 5O2 --> 3CO2 + 4H20 (3 cabon - check; 8 hydrogen - check; 10 oxygen - check).

a) In the equation there is a 5:1 ratio between propane and oxygen. We also know that number of mole is proportional to pressure and volume. Since pressure is constant (STP) then the volume of O2 is 7.2 * 5 = 36 litres.

b) For a near ideal gas that PV = nRT (combined gas law). So for 7.2 litres propane we find n(propane) = 101.3 * 7.2/8.314*298 ~ 0.29 mole (using metric units throughout for simplicity).

There is a 1:3 ratio between propane and CO2. Therefore 3 * 0.29 = 0.87 mole of CO2 is produced.

MW(CO2) ~ 44 g/mol. Therefore m(CO2) = 44 * 0.87 ~ 38.3 g

c) We know we need more oxygen than propane (due to the 1:5 ratio) so oxygen is the limiting reagent. Again Volume is proportional to number of mole and we see there is a 5:4 ratio between oxygen and water. Therefore the volume of water vapour produced will be (4/5) * 15 = 12 litres.

The other questions use the same technique and will give you some much needed practice.

Explanation:

7 0

3 years ago