All categories

3 years ago

What’s the correct answer !!

Chemistry

1 answer:

Sati [7]3 years ago

6 0

Answer:

From my side the correct option is "A"

Explanation: Reasons for its correction are ,

1) Highly reactive: Nanoparticles are therefore extremely unstable and easily change themselves or react with active substances to reach a relatively stable state in some cases. This causes desired changes or undesired changes to nanoparticles and thus makes them exhibit a high reactivity and a poor stability.

2)Small size: Nanotechnology can provide rapid and sensitive detection of cancer-related molecules, enabling scientists to detect molecular changes even when they occur only in a small percentage of cells. Nanotechnology also has the potential to generate entirely novel and highly effective therapeutic agents.

You might be interested in

How to determine reaction order in reactant?

Artyom0805 [142]

In order to determine, Order of reaction, we have to add all the exponents written in the Chemical form, on the Reactant species.

Hope this helps!

8 0

3 years ago

Hi ! Could someone help me out with this last part to my chemistry practice ? Thank you !

skelet666 [1.2K]

After 100years, sample is 250g

After 200 years, sample is 125g

After 300years, sample is 62.5 g

7 0

3 years ago

A sample initially contained 150 mg of radon-222. After 11.4 days only 18.75mg of the radon-222 in the sample remained. How many

beks73 [17]

<u>Answer: </u>

A sample initially contained 150 mg of radon-222. After 11.4 days only 18.75mg of the radon-222 in the sample remained where 3 half-lives have passed

<u>Explanation:</u>

Given, the initial value of the sample, $A_0$ = 150mg

Final value of the sample or the quantity left, A = 18.75mg

Time = 11.4 days

The amount left after first half life will be ½.

The number of half-life is calculated by the formula

$\frac{A}{A_{0}}=\left(\frac{1}{2}\right)^{N}$

where N is the no. of half life

Substituting the values,

$\frac{18.75}{150}=\left(\frac{1}{2}\right)^{N}$

$\left(\frac{1}{2}\right)^{3}=\left(\frac{1}{2}\right)^{N}$

On equating, we get, N = 3

Therefore, 3 half-lives have passed.

7 0

3 years ago

Calculate the hydronium ion concentration in an aqueous solution with a poh of 4.33 at 25°c.

Jlenok [28]

Taking into account the definition of pH and pOH, the hydronium ion concentration in an aqueous solution with a pOH of 4.33 at 25°c is 2.138×10⁻¹⁰ M.

<h3>Definition of pH</h3>

pH is a measure of acidity or alkalinity that indicates the amount of hydrogen ions present in a solution or substance.

The pH is defined as the negative base 10 logarithm of the activity of hydrogen ions, that is, the concentration of hydrogen ions or hydronium ion H₃O⁺:

pH= - log [H⁺]= - log [H₃O⁺]

<h3>Definition of pOH</h3>

Similarly, pOH is a measure of hydroxyl ions in a solution and is expressed as the logarithm of the concentration of OH⁻ ions, with the sign changed:

pOH= - log [OH⁻]

<h3>Relationship between pH and pOH</h3>

The following relationship can be established between pH and pOH:

pOH + pH= 14

<h3>Concentration of hydronium ions</h3>

Being pOH= 4.33, pH is calculated as:

pH + 4.33= 14

pH= 14 - 4.33

Replacing in the definition of pH the concentration of hydronium ions is obtained:

- log [H₃O⁺]= 9.67

Solving:

[H₃O⁺]= 10⁻⁹ ⁶⁷

Finally, the hydronium ion concentration in an aqueous solution with a pOH of 4.33 at 25°c is 2.138×10⁻¹⁰ M.

Learn more about pH and pOH:

brainly.com/question/16032912

brainly.com/question/13557815

#SPJ1

4 0

2 years ago

The Positively charged center of an atom is called

Rashid [163]

Answer: The Nucleus: The Center of an Atom. The nucleus, that dense central core of the atom, contains both protons and neutrons. Electrons are outside the nucleus in energy levels. Protons have a positive charge, neutrons have no charge, and electrons have a negative charge.

5 0

3 years ago