What is a,well designed experiment called?

Predict the mass of iron (III) sulfide produced when 3.0 g of iron filings react completely with 2.5 g of yellow sulfur solid, S

777dan777 [17]

1) Chemical equation

16Fe(s) + 3S8(s) ---> 8Fe2S3

2) Molar ratios:

16 mol Fe : 3 mole S8 : 8 mol Fe2S3

3) Convert masses in grams to number of moles

number of moles = mass in grams / molar mass

a) iron, Fe

mass = 3.0 g
atomic mass = 55.845 g/mol

=> number of moles of Fe = 3.0g / 55.845 g/mol = 0.0537 mol

b) Sulfur, S8

mass = 2.5 g
molar mass = 8*32.065 g/mol = 256.52 g/mol

=> number of moles of S8 = 2.5g / 256.52 g/mol = 0.009746 mol

4) Limiting reactant

Theoretical ratio                           actual ratio

16 mol Fe / 3 mol S8                 0.0537 mol Fe / 0.009746 mol S8

5.33                                               5.50

So, there is a little bit more Fe than the theoretical needed to react all the S8, which means the S8 is the limiting reactant.

5) Calculate the number of moles of iron (III) produced with 2.5 g (0.009746 moles) of S8

3moles S8 / 8 moles Fe2S3 = 0.009746 moles S8 / x

=> x = 0.009746 * 8 / 3 moles Fe2S3 = 0.026 moles Fe2S3

6) Convert 0.026 moles Fe2S3 into grams

mass in grams = number of moles * molar mass

molar mass of Fe2S3 = 207.9 g/mol

mass = 0.026 mol * 207.9 g/mol = 5.40 g

7) Answer: option D)

3 0

3 years ago

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Provide the IUPAC names for

ollegr [7]

Answer:

For a: The IUPAC name of the compound is N-ethylethaneamide.

For b: The IUPAC name of the compound is N,N-diethylmethaneamide.

For c: The IUPAC name of the compound is ethyl pentanoate

Explanation:

To name a compound, first look for the longest possible carbon chain.

For a:

Amide group is a type of functional group where an amine group is attached to a carbonyl group. The general formula of amide is $R-CO-NH_2$ , where R is an alkyl or aryl group.

In part (a), the alkyl group has 2 carbon atoms and thus, the prefix used is 'eth-'

Also, an ethyl substituent is directly attached to N-atom. It is an alkane structured hydrocarbon thus, the suffix used will be '-ane'

Hence, the IUPAC name of the compound is N-ethylethaneamide.

For b:

Amide group is a type of functional group where an amine group is attached to a carbonyl group. The general formula of amide is $R-CO-NH_2$ , where R is an alkyl or aryl group.

In part (b), the alkyl group has 1 carbon atoms and thus, the prefix used is 'meth-'

Also, two ethyl substituents are directly attached to N-atom. It is an alkane structured hydrocarbon thus, the suffix used will be '-ane'

Hence, the IUPAC name of the compound is N,N-diethylmethaneamide.

For c:

Esters are a kind of organic molecules having functional groups, $R-COO-R'$ where R and R' are the alkyl or aryl groups. They are formed by the combination of alcohol and carboxylic acid.

These functional group compounds are named in two words which is alkyl alkanoates, where alkyl refers to the alcoholic part and alkanoate refers to the carboxylic acid part of the molecule. The numbering of the parent chain in esters is done from the carboxylic carbon. The alkyl part is not given any numbers.

In part (c), there are 5 carbon atoms present in a straight chain and thus, the prefix used is 'pent-'

Also, an ethyl group forms the alcoholic part.

Hence, the IUPAC name of the compound is ethyl pentanoate

6 0

3 years ago

After moving down a group in the periodic table, the number of valence electrons

Delvig [45]

the number of Valence electrons remains the same

8 0

2 years ago

Which of the following would be useful to show the growth rate of plants at varying temperatures? A. circle graph B. bar graph C

Pepsi [2]

Answer: Im thinking the answer Is B) Bar graph?

Explanation:

7 0

3 years ago

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Given the following unbalanced chemical reaction: As + NaOH Na3AsO3 + H2 What would be the coefficient of the NaOH molecule in t

barxatty [35]

Answer: -

6

Explanation: -

The given unbalanced chemical equation is As + NaOH -- > Na3AsO3 + H2

We see there 3 sodium on the right side from Na3AsO3.

But there are only 1 sodium on the left from NaOH.

So we multiply NaOH by 3.

As + 3 NaOH -- > Na3AsO3 + H2

Now we see the number of Hydrogen on the left is 3.

But the number of hydrogens is 2 on the left.

So, we multiply to get both sides 6 hydrogen.

As + 6NaOH -- > Na3AsO3 + 3 H2

Rebalancing for Na,

As + 6NaOH -- > 2Na3AsO3 + 3 H2.

Finally balancing As,

2 As + 6 NaOH -- > 2Na3AsO3 + 3H2

The coefficient of the NaOH molecule in the balanced reaction is thus 6

7 0

3 years ago