How do the properties of elements change as you move across a period

Green plants use light from the sun to drive photosynthesis. photosynthesis is a chemical reaction in which water (H2O) and carb

alexandr1967 [171]

Answer:

Mass of H₂O is 3.0g

Explanation:

The reaction equation is given as:

6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

Parameters that are known:

Mass of CO₂ used = 7.3g

Unknown: mass of water consumed = ?

Solution

To solve this kind of problem, we simply apply some mole concept relationships.

First, we work from the known to the unknown. From the problem, we have 7.3g of CO₂ that was used. We can find the number of moles from this value using the expression below:

Number of moles of CO₂ = $\frac{mass}{molar mass}$

From this number of moles of CO₂, we can use the balanced equation to relate the number of moles of CO₂ to that of H₂O:

6 moles of CO₂ reacted with 6 moles of H₂O(1:1)

We can then use the mole relationship with mass to find the unknown.

Workings

>>>> Number of moles of CO₂ =?

Molar mass of CO₂ :

Atomic mass of C = 12g

Atomic mass of O = 16g

Molar mass of CO₂ = 12 + (2 x16) = 44gmol⁻¹

Number of moles of CO₂ = $\frac{7.3}{44}$ = 0.166moles

>>>>>> if 6 moles of CO₂ reacted with 6 moles of H₂O, then 0.166moles of CO₂ would produce 0.166moles of H₂O

>>>>>> Mass of water consumed = number of mole of H₂O x molar mass

Mass of H₂0 = 0.166 x ?

Molar mass of H₂O:

Atomic mass of H = 1g

Atomic mass of O = 16

Molar mass of H₂O = (2x1) + 16 = 18gmol⁻¹

Mass of H₂O = 0.166 x 18 = 3.0g

7 0

4 years ago

Specific amino acids that line the selectivity filter of the K channel can dehydrate K and allow passage of that ion but cannot

Bogdan [553]

Answer:

Hi

True

Explanation:

Since on the inner and outer surfaces of the membrane, a series of negatively charged amino acids are found, which increase the local concentration of cations. The path of the ions begins on the inner surface filled with water molecules where the ion can retain its hydration sphere. Two thirds of its interior in the membrane the inside of the channel narrows in the region of the selectivity filter, forcing the ion to separate from the water molecules. Oxygen atoms in the selectivity filter replace the water molecules in the K+ hydration sphere, forming a series of coordination spheres through which the ion moves. The preferential stabilization of K+ against Na+ is the basis of the ion selectivity of this filter.

5 0

3 years ago

Butter melt when you heat it in a pan on the stove. Is this a chemical change or physical change? How can you tell?

choli [55]

It would be an physical change ; if you melt butter the butter goes from a solid to a liquid so therefore the physical state is changed.

4 0

3 years ago

In general how are word equations written to describe chemical equations

Alexus [3.1K]

<span>chemicals reacting are written on the left, what is formed is written on the right after the = sign

eg Copper + oxygen = copper oxide.
Hope this helps , mark as brainliest and say thanks THANKS..</span>

5 0

3 years ago

A mysterious white powder could be powdered sugar (C12H22O11), cocaine (C17H21NO4), codeine (C18H21NO3), norfenefrine (C8H11NO2)

rodikova [14]

Norfenefrine (C₈H₁₁NO₂).

<h3>Further explanation</h3>

We will solve a case related to one of the colligative properties, namely freezing point depression.

The freezing point of the solution is the temperature at which the solution begins to freeze. The difference between the freezing point of the solvent and the freezing point of the solution is called freezing point depression.

$\boxed{ \ \Delta T_f = T_f(solvent) - T_f(solution) \ } \rightarrow \boxed{ \ \Delta T_f = K_f \times molality \ }$

<u>Given:</u>

A mysterious white powder could be,

powdered sugar (C₁₂H₂₂O₁₁) with a molar mass of 342.30 g/moles,
cocaine (C₁₇H₂₁NO₄) with a molar mass of 303.35 g/moles,
codeine (C₁₈H₂₁NO₃) with a molar mass of 299.36 g/moles,
norfenefrine (C₈H₁₁NO₂) with a molar mass of 153.18 g/moles, or
fructose (C₆H₁₂O₆) with a molar mass of 180.16 g/moles.

When 82 mg of the powder is dissolved in 1.50 mL of ethanol (density = 0.789 g/cm³, normal freezing point −114.6°C, Kf = 1.99°C/m), the freezing point is lowered to −115.5°C.

<u>Question: </u>What is the identity of the white powder?

<u>The Process:</u>

Let us identify the solute, the solvent, initial, and final temperatures.

The solute = the powder
The solvent = ethanol
The freezing point of the solvent = −114.6°C
The freezing point of the solution = −115.5°C

Prepare masses of solutes and solvents.

Mass of solute = 82 mg = 0.082 g
Mass of solvent = density x volume, i.e., $\boxed{ \ 0.789 \ \frac{g}{cm^3} \times 1.50 \ cm^3 = 1.1835 \ g = 0.00118 \ kg \ }$

We must prepare the solvent mass unit in kg because the unit of molality is the mole of the solute divided by the mass of the solvent in kg.

The molality formula is as follows:

$\boxed{ \ m = \frac{moles \ of \ solute}{kg \ of \ solvent} \ } \rightarrow \boxed{ \ m = \frac{mass \ of \ solute \ (g)}{molar \ mass \ of \ solute \times kg \ of \ solvent} \ }$

Now we combine it with the formula of freezing point depression.

$\boxed{ \ \Delta T_f = K_f \times \frac{mass \ of \ solute \ (g)}{molar \ mass \ of \ solute \times kg \ of \ solvent} \ }$

It is clear that we will determine the molar mass of the solute (denoted by Mr).

We enter all data into the formula.

$\boxed{ \ -114.6^0C - (-115.5^0C) = 1.99 \frac{^0C}{m} \times \frac{0.082 \ g}{Mr \times 0.00118 \ kg} \ }$

$\boxed{ \ 0.9 = \frac{1.99 \times 0.082}{Mr \times 0.00118} \ }$

$\boxed{ \ Mr = \frac{0.16318}{0.9 \times 0.00118} \ }$

We get $\boxed{ \ Mr = 153.65 \ }$

These results are very close to the molar mass of norfenefrine which is 153.18 g/mol. Thus the white powder is norfenefrine.

<h3>Learn more</h3>

The molality and mole fraction of water brainly.com/question/10861444
About the mass and density of ethylene glycol as an antifreeze brainly.com/question/4053884
About the solution as a homogeneous mixture brainly.com/question/637791

Keywords: a mysterious white powder, sugar, cocaine, codeine, norfenefrine, fructose, the solute, the solvent, dissolved, ethanol, normal freezing point, the freezing point depression, the identity

7 0

3 years ago

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