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3 years ago

28.

Chemistry

1 answer:

allochka39001 [22]3 years ago

6 0

Answer: I believe that B) require target cell receptors to illicit a target cell response, is the right answer.

Explanation:

You might be interested in

Atoms of which element have the most valence electrons? A. Nitrogen (N) B. Sodium (Na) C. Oxygen (O) D. Calcium (Ca)

evablogger [386]

C.oxygen
It has 6 valence electrons

6 0

3 years ago

When 80.0 mL of a 0.812 M barium chloride solution is combined with 40 mL of a 1.52 M potassium sulfate solution, 10.8 g of bari

BabaBlast [244]

Answer:

76.1%

Explanation:

The reaction that takes place is:

BaCl₂ + K₂SO₄ → BaSO₄ + 2KCl

First we determine how many moles of each reactant were added:

BaCl₂ ⇒ 80 mL * 0.812 M = 64.96 mmol BaCl₂

K₂SO₄ ⇒ 40 mL * 1.52 M = 60.8 mmol K₂SO₄

Thus K₂SO₄ is the limiting reactant.

Using the <em>moles of the limiting reactant</em> we <u>calculate how many moles of BaSO₄ would have been produced if the % yield was 100%</u>:

60.8 mmol K₂SO₄ * $\frac{1mmolBaSO_4}{1mmolK_2SO_4}$ = 60.8 mmol BaSO₄

Then we <u>convert that theoretical amount into grams</u>, using the <em>molar mass of BaSO₄</em>:

60.8 mmol BaSO₄ * 233.38 mg/mmol = 14189.504 mg BaSO₄

14189.504 mg BaSO₄ / 1000 = 14.2 g BaSO₄

Finally we calculate the % yield:

% yield = 10.8 g / 14.2 g * 100 %

% yield = 76.1%

7 0

3 years ago

If a neutral atom of oxygen has 8 protons, 8 electrons, and 7 neutrons, what number is the mass number of this atom?

irakobra [83]

Mass number = number of protons + number of neutrons

mass number= 8 + 7= 15 ---> the answer is B.

4 0

4 years ago

A 1.775g sample mixture of potassium hydrogen carbonate is decomposed by heating. if the mass loss is 0.275g what is the percent

Marina86 [1]

A 1.775g sample mixture of KHCO₃ is decomposed by heating. if the mass loss is 0.275g, the mass percentage of KHCO₃ is 70.4%.

<h3>What is a decomposition reaction?</h3>

A decomposition reaction can be defined as a chemical reaction in which one reactant breaks down into two or more products.

Step 1: Write the balanced equation for the decomposition of KHCO₃.

2 KHCO₃(s) → K₂CO₃(s) + CO₂(g) + H₂O(l)

The mass loss of 0.275 g is due to the gaseous CO₂ that escapes the sample.

Step 2: Calculate the mass of KHCO₃ that formed 0.275 g of CO₂.

In the balanced equation, the mass ratio of KHCO₃ to CO₂ is 200.24:44.01.

0.275 g CO₂ × 200.24 g KHCO₃/44.01 g CO₂ = 1.25 g KHCO₃

Step 3: Calculate the mass percentage of KHCO₃ in the sample.

There are 1.25 g of KHCO₃ in the 1.775 g sample.

%KHCO₃ = 1.25 g/1.775 g × 100% = 70.4%

A 1.775g sample mixture of KHCO₃ is decomposed by heating. if the mass loss is 0.275g, the mass percentage of KHCO₃ is 70.4%.

Learn more about decomposition reactions here: brainly.com/question/14219426

7 0

2 years ago

PLEASE HELP ME ASAP!!!! WILL GIVE BRAINLIEST TO FIRST CORRECT ANSWER!!!!!!! THANKS:)

VikaD [51]

Answer:

Explanation:

1. How many molecules are present in 3 moles of silicon dioxide (sio2)

A. 5.00 x 10^23

B. 6.02 x 10^23

C. 12.36 x 10^23

D. 18.06 x 10^23

Answer:

18.066 × 10²³atoms

Explanation:

Given data:

Moles of silicon dioxide = 3 mol

Number of molecules = ?

Solution:

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.

The number 6.022 × 10²³ is called Avogadro number.

For example,

one mole = 6.022 × 10²³ atoms

3 mole × 6.022 × 10²³ atoms / 1mol

18.066 × 10²³atoms

2. What is the molar mass of Ag2S?

Answer:

Molar mass of Ag₂S = 247.8014 g/mol

Explanation:

The molar mass of a chemical compound is sum of atomic mass of all constituent atoms.

For Ag₂S

Atomic mass of Ag = 107.8682 amu

Atomic mass of S = 32.065 amu

There are two silver atoms that's why

107.8682 amu × 2= 215.7364

Molar mass of Ag₂S:

Molar mass of Ag₂S = 215.7364 + 32.065

Molar mass of Ag₂S = 247.8014 g/mol

3) In the balanced equation 4KO + 2CO2 = 2K2CO3 + CO3 Which two chemicals have a molar ratio of 3:4?

Answer:

The equation:

4KO₂ + 2CO₂ → 2K₂CO₃ + 3O₂

In this balanced equation oxygen and potassium superoxide have ration 3:4.

Explanation:

Chemical equation:

4KO + 2CO₂ → 2K₂CO₃ + CO₃

The given equation does not have any two chemical ration 3:4.

The equation:

4KO₂ + 2CO₂ → 2K₂CO₃ + 3O₂

In this balanced equation oxygen and potassium superoxide have ration 3:4.

Coefficient with reactant and product.

Reactant Product

KO₂ = 4 K₂CO₃ = 2

CO₂ = 2 O₂ = 3

So KO₂ and oxygen have molar ratio 3 : 4 in balanced chemical equation.

7 0

4 years ago