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3 years ago

When must scientist conduct controlled experiments ?

1 answer:

8 0

Usually when scientist wants to test whether one compound or one phenotype is related to another phenotype. Then they need to control this variable when conducting experiments.

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How many moles of NH3 would be formed from the complete reaction of 16.0 g H2?

natima [27]

Taking into account the reaction stoichiometry, 5.33 moles of NH₃ are formed from the complete reaction of 16 grams of H₂.

<h3>Reaction stoichiometry</h3>

In first place, the balanced reaction is:

N₂ + 3 H₂ → 2 NH₃

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:

N₂: 1 mole
H₂: 3 moles
NH₃: 2 moles

The molar mass of the compounds is:

N₂: 14 g/mole
H₂: 2 g/mole
NH₃: 17 g/mole

Then, by reaction stoichiometry, the following mass quantities of each compound participate in the reaction:

N₂: 1 mole ×14 g/mole= 14 grams
H₂: 3 moles ×2 g/mole= 6 grams
NH₃: 2 moles ×17 g/mole=34 grams

<h3>Mass of NH₃ formed</h3>

The following rule of three can be applied: if by reaction stoichiometry 6 grams of H₂ form 2 moles of NH₃, 16 grams of H₂ form how many moles of NH₃?

$moles of NH_{3}= \frac{16 grams of H_{2} x2moles of NH_{3}}{6 grams of H_{2}}$

<u><em>moles of NH₃= 5.33 moles</em></u>

Then, 5.33 moles of NH₃ are formed from the complete reaction of 16 grams of H₂.

Learn more about the reaction stoichiometry:

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4 0

2 years ago

Please help me if possible<br>

Gwar [14]

Explanation:

RAM={mass number ×relative abundance (%) + mass number ×relative abundance (%)} ÷100%

so take (91.05×20) +(8.95×22)

5 0

2 years ago

Chemistry!! Please help!!

cluponka [151]

Answer:

4.993 ×10⁻¹¹ J

Explanation:

The <em>nuclear binding energy</em> is the energy equivalent to the mass defect.

The <em>mass defect</em> is the difference between the mass of a nucleus and the sum of the masses of its nucleons.

<em>Calculate the mass defect </em>

16 p = 16 × 1.007 28 u = 16.116 48 u

16 n = 16 × 1.008 67 u = 16.138 72 u

Total mass of nucleons = 32.255 20 u

- Mass of S-32 = <u>31.972 070 u </u>

Mass defect = 0.283 13 u

Convert the <em>unified atomic mass units to kilograms</em>.

Mass defect

$= \text{0.283 13 u} \times \frac{ \text{1.66 06} \times 10^{-27} \text{ kg}}{\text{1 u}}$

$= 4.700 \times 10^{-28} \text{ kg}$

Use Einstein’s equation to <em>convert the mass defect into energy</em>

$E = mc^{2}$

$E = 4.7000 \times 10^{-28} \text{ kg} \times (2.998 \times 10^{8} \text{ m}\cdot\text{s}^{-1})^{2} = 4.224 \times 10^{-11} \text{ J}$

4 0

3 years ago

Nick hypothesizes that wax has a higher melting point than chocolate how can he test his hypothesis

LUCKY_DIMON [66]

Melt chocolate and measure the temperature and then melt wax and measure the temperature and compare his results.

5 0

3 years ago

What is the sequence of energy transformations that occur in a nuclear reactor?

GuDViN [60]

Answer:

option (B) is correct

Explanation:

In case of nuclear reactors first the nuclear energy is emitted due to the nuclear fission of heavy elements.

This nuclear energy is emitted in the form of heat energy.

This heat energy is used to rotate the turbines, that means it is converted in the form of mechanical energy and then finally this mechanical energy is converted into electrical energy.

4 0

3 years ago