Ni is the symbol for what element?

Caffeine, a stimulant found in coffee, tea, and certain soft drinks, contains C, H, O, and N. Combustion of 1.000 mg of caffeine

Yuliya22 [10]

Answer:

<u>194 g/mol</u>

Explanation:

<u>1) Content of C:</u>

All the C atoms in the 1.000 mg of caffeine will be found in the 1.813 mg of CO₂.

Mass of C in 1.813 mg of CO₂

Since the atomic mass of C is 12.01 g/mol and the molar of of CO₂ is 44.01, there are 12 mg of C in 44 mg of CO₂ and you can set the proporton:

12.01 mg C / 44.01 mg CO₂ = x / 1.813 g CO₂

⇒ x = 1.813 × 12.01 / 44.01 g of C = 0.49475 mg of C

Number of moles of C

number of moles = mass in g / atomic mass = 0.49475×10⁻³ g / 12.01 g/mol = 4.1195×10⁻⁵ moles = 0.041195 milimol

<u>2) Content of H</u>

All the H atoms in the 1.000 mg of caffeine will be found in the 0.4639 mg of H₂O

Mass of H in 0.4639 mg of H₂O

Since the atomic mass of H is 1.008 g/mol and the molar of of H₂O is 18.015 g/mol, there are 2×1.008 mg of H in 18.015 mg of H₂O and you can set the proporton:

2×1.008 mg H / 18.015 mg H₂O = x / 0.4639 mg H₂O

⇒ x = 0.4639 mg H₂O × 2 × 1.008 mg H / 18.015 mg H₂O = 0.051913 mg H

Number of moles of H

number of moles = mass in g / atomic mass = 0.051913 ×10⁻³ g / 1.008 g/mol = 5.1501× 10⁻⁵ moles = 0.051501 milimol

<u>3) Content of N</u>

All the N atoms in the 1.000 mg of caffeine will be found in the 0.2885 mg of N₂

Mass of N in 0.2885 mg of N₂ is 0.2885 mg

Number of moles of N

number of moles = mass in g / atomic mass = 0.2885 ×10⁻³ g / 14.007 g/mol = 2.0597× 10⁻⁵ moles = 0.020597 milimol

<u>4) Content of O</u>

The mass of O is calculated by difference:

Mass of O = mass of sample - mass of C - mass of H - mass of N

Mass of O = 1.000 mg - 0.49475 mg C - 0.051913 mg H - 0.2885 mg N

Mass of O = 0.1648 mg

Moles of O = 0.1648 × 10 ⁻³ g / 15.999 g/mol = 1.0303×10⁻⁵ mol = 0.01030 milimol

<u>5) Ratios</u>

Divide every number of mililmoles by the smallest number of milimoles:

C: 0.041195 / 0.01030 = 4
H: 0.051501 / 0.01030 = 5
N: 0.020597 / 0.01030 = 2

O: 0.01030 / 0.01030 = 1

C: 4
H: 5
N: 2
O: 1

<u>6) Empirical formula:</u>

C₄H₅N₂O₁

<u>7) Calculate the approximate mass of the empirical formula:</u>

4 × 12 + 5 × 1 + 2 × 14 + 1 × 16 = 97 g/mol

So, since that number is not between 150 and 200 g/mol, multiply by 2: 97 × 2 = 194, which is between 150 and 200.

Thus, the estimate is 194 g/mol

7 0

3 years ago

What type of Weathering is important to sand storms on Mars? Physical or

KIM [24]

Answer:

1. Physical Weathering

2. Option B

Explanation:

1. Physical weathering

On Mars, there are two types of weathering agents a) wind and b) acid fog. Thus, they will carry out only physical weathering

2. Option B

3D can be used to produce things that are required on the Mars and also the locally available raw material can be used for printing thereby saving the cost.

3 0

3 years ago

The diagram above shows the repeating groups of atoms that make

Reil [10]

a a a a a a a a a a a a a a. as a a a a. as. a I don't no the answer

4 0

3 years ago

A car with a mass of 900 kg accelerates at 1.5 m/s2 what is the force acting on the car?

Alex73 [517]

Answer:

10500 N

Explanation:

f = ma

f = 900*1.5

f = 10500 N

7 0

3 years ago

Nearly every compound of silicon has the element in the ⁺4 oxidation state. In contrast, most compounds of lead have the element

baherus [9]

Boron shows analogous behaviour with silicon. Every compound of Boron have +3 oxidation state, while as we go down the the oxidation state become +1 and +3. For example, gallium, indium, etc.

Similarly, every compound of silicon has the element in the ⁺4 oxidation state. In contrast, most compounds of lead have the element in the ⁺2 state because of inert pair effect.

<h3>What is Inert pair effect? </h3>

The inert-pair effect is defined as the tendency of two electrons in the outermost atomic s-orbital almost remain unshared in the compounds of the post-transition metals.

<h3>How we calculate Oxidation state? </h3>

Each atom in an element either be in its uncombined or free state has oxidation number of zero. Such as each atom in H₂, Cl₂ , P4, ,O₂ , Na, Al, O3, S8, and Mg, all have an oxidation number zero.
The oxidation state of ions that comprise of only one atom is the actual charge on the ion.
The oxidation state of hydrogen is +1, excluding when it is bonded to metals having two elements. For example, CaH2, its oxidation state is –1.
Fluorine and other halogens have an oxidation state equal to –1 when they appear as a form of halide ions in their compounds.

Since the inert pair effect increases as we go down the group and become more predominant, therefore, the stability of +2 oxidation state goes on increasing down the group. Therefore, gallium, indium are mostly found in +1 oxidation state.

Thus, we concluded that Boron shows analogous behaviour with silicon. Every compound of Boron have +3 oxidation state, while as we go down the the oxidation state become +1 and +3. For example, gallium, indium, etc.

learn more about oxidation state:

brainly.com/question/25551544

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4 0

2 years ago