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3 years ago

When chemists write out reactions, they often place numbers to the left of a chemical formula.

Chemistry

2 answers:

guajiro [1.7K]3 years ago

5 0

The number to the left of a chemical formula is called coefficients

Explanation

Coefficient is the number in front of a chemical formula.

It tell how many molecules of a given formula that are involved in a chemical reaction.

in 2H+O→ H2O the coefficient are 2,1,1

that is, 2 in front of H2

1 in front of O

1 in front of H2O

nikitadnepr [17]3 years ago

4 0

Answer: The correct answer is coefficients.

Explanation:

Coefficients are defined as the numbers which are written in front of the atoms or molecules in a chemical reaction. They represent the number of moles of substance in a chemical reaction.

Subscript numbers are defined as the number of atoms of each element present in a compound.

Superscript numbers are defined as the charges of ions reacting in a chemical reaction.

For Example: Dissociation of sodium carbonate into its ions, the equation follows:

$Na_2CO_3\rightarrow 2Na^++CO_3^{2-}$

The number '2' on the left side written in the subscript of sodium ion represents the number of sodium atoms.

The number '2' on right side written in front of sodium ion represents the number of moles of sodium ions.

The number '(2-)' on right side written in the superscript of carbonate ion represents the charge on carbonate ion.

Hence, the correct answer is coefficients.

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If 7.36 g of sodium metal react, how many grams of sodium hydroxide can be produced

8090 [49]

You would also need to know the mol of sodium. After knowing the mol, write down the reaction;
Na + H20 -> NaOH + H2
Use the mol ratio, to find the amount of mol of sodium hydroxide. (Remember to balance the equation first)
After you have the necessary variables, use the following formula:
mass of sodium hydroxide = mol of sodium hydroxide x molar mass (relative/formula mass of sodium hydroxide)
That is how you will find the mass of sodium hydroxide.

8 0

3 years ago

Give the chemical symbol for the element with the ground‑state electron configuration [ Ar ] 4 s 2 3 d 1 . symbol: Determine the

Rus_ich [418]

Answer:

Sc (Scandium) has the given electronic configuration.

Explanation:

The given electronic configuration is [Ar] $4s^{2}3d^{1}$ .

The last electron enters the d-subshell and hence is a d-block element known as Scandium with chemical symbol Sc.

For 4s subshell

n=4,l=0 and m ranges from -l to +l so m=0.

For 3d subshell

n=3,l=2 and m ranges from -l to +l so m can take values -2,-1,0,+1,+2

Note:

l values for subshells:

s : 0

p : 1

d : 2

f : 3 and so on.

5 0

3 years ago

The density of whole blood is 1.05 g/ml. a typical adult has between 4.7 and 5.5 l of whole blood. what is the mass in pounds of

Kisachek [45]

1.05 g/ml * 1000 ml = 1050g/l because of 1g/ml = 1 kg/l so, a/q mass of 4.7 l of whole blood in pound = 4.7 * 1050 = 4935 g so in pound 4935g = 10.87981p

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3 years ago

Work is equal to the what used and multiplyed by the what over which the force was applied

Allushta [10]

W=Fd
Work is equal to the force multiplied by the distance travelled.

4 0

4 years ago

Write the empirical formula of at least four binary ionic compounds that could be formed from the following ions: Zn2+, Ni4+, F-

hram777 [196]

Ionic compounds are formed between oppositely charged ions.

A binary ionic compound is composed of ions of two different elements - one of which is a positive ion(metal), and the other is negative ion (nonmetal).

To write the empirical formula of binary ionic compound we must remember that one ion should be positive and other ion should be negative, then only the correct formula should be written. To write the empirical formula the charges of opposite ions should be criss-crossed.

First empirical formula of binary ionic compound is written between $Zn^{2+} (Positive ion)and F^{-} (Negative ion)$

First Formula would be $ZnF_{2}$

Second empirical formula is between $Zn^{2+}(Positive ion) and O^{2-}(Negative ion)$

Second Formula would be $Zn_{2}O_{2}$

Note : When the subscript are same they get cancel out, so $Zn_{2}O_{2}$ would be written as $ZnO$

Third empirical formula is between $Ni^{4+}(Positive ion) and F^{-}(Negative ion)$

Third Formula would be : $NiF_{4}$

Forth empirical formula is between $Ni^{4+}(Positive ion)and O^{2-}(negative ion)$

Forth Formula would be : $Ni_{2}O_{4}$ or $NiO_{2}$

Note- The subscript will be simplified and the formula will be written as $NiO_{2}$ .

The empirical formula of four binary ionic compounds are : $ZnF_{2}, ZnO, NiF_{4},NiO_{2}$

8 0

3 years ago

Read 2 more answers