How many protons, neutrons, and electrons does a magnesium atom with a mass number of 25 contain?

Science thing............<br><br> Select the correct answer ♡

Alika [10]

Answer:

d

Explanation:

sugar molecules are being broken down

3 0

3 years ago

Breaking an object such as a mirror is an example of physical change, chemical change,physical reaction, chemical reaction

dangina [55]

Answer:

option A= Physical change

Explanation:

physical change:

" It is a change in which no new substance is formed"

Breaking of object like glass is the example of physical change because it is not change into another object. It effect the form of object but can not change the chemical composition.

Chemical changes:

" it is a change in which one substance is converted into new product through chemical reaction".

During the chemical changes the types and the number of atom remain same but their arrangement changed.

for example: burning of wood, baking of cake, digesting food, resting of iron etc.

Physical reaction:

" physical reaction occur during the molecular rearrangement. There is no chemical change occur"

In this type of changes no bonds are break to form new bonds, for example boiling point.

Chemical reaction:

" chemical reaction occur when molecules are chemically react with each others and bonds formation and breaking is also occur"

5 0

3 years ago

What change causes a substance to change states of matter?

pochemuha

If the states of matter have changed such as from solid to liquid, you have to remove or add energy.

3 0

3 years ago

Read 2 more answers

A sample of pure calcium fluoride with a mass of 15.0 g contains 7.70 g of calcium. how much calcium is contained in 45.0 g of c

kolbaska11 [484]

In a sample of pure calcium fluoride of mass 15.0 g, 7.70 g of calcium is present. First convert the mass into number of moles as follows:

$n=\frac{m}{M}$

Here, m is mass and M is molar mass.

Molar mass of Ca is 40 g/mol, putting the values,

$n=\frac{7.70 g}{40 g/mol}=0.1925 mol$

Similarly, molar mass of $CaF_{2}$ is 78.07 g/mol thus, number of moles will be:

$n=\frac{15.0 g}{78.07 g/mol}=0.1921 mol$ .

Thus, 0.1921 mol of $CaF_{2}$ have 0.1925 mol of Ca, or 1 mole of $CaF_{2}$ will have approximately 1 mole of Ca.

Now, mass of Ca needs to be calculated in 45.0 g of $CaF_{2}$ . Converting mass into number of moles first,

$n=\frac{45.0 g}{78.07 g/mol}=0.5764 mol$

Thus, number of moles of Ca will also be 0.5764 mol, converting number of moles into mass,

$m=n\times M=0.5764 mol\times 40 g/mol=23.06 g$

Therefore, mass of Ca will be 23.06 g.

6 0

3 years ago

An atom of argon has a radius rar = 88 pm and an average speed in the gas phase at 25°C of 172 m/s.

Rudik [331]

Answer:

1.2* 10³ rNe.

Explanation:

Given speed of neon=350 m/s

Un-certainity in speed= (0.01/100) *350 =0.035 m/s

As per heisenberg uncertainity principle

Δx*mΔv ≥\frac{h}{4\pi }

4π

h

..................(1)

mass of neon atom =\frac{20*10^{-3} }{6.22*10^{-23} } =3.35*10^{-26} kg

6.22∗10

−23

20∗10

−3

=3.35∗10

−26

kg

substituating the values in eq. (1)

Δx =4.49*10^{-8}10

−8

m

In terms of rNe i.e 38 pm= 38*10^{-12}10

−12

Δx=\frac{4.49*10^{-8} }{38*10^{-12} }

38∗10

−12

4.49∗10

−8

=0.118*10^{4}10

4

* (rNe)

=1.18*10³ rN

= 1.2* 10³ rNe.

Explanation:

This is the answer

7 0

3 years ago