The force of attraction between two masses of different substances that are in contact

The atomic mass of magnesium is the weighted average of the atomic masses of

Debora [2.8K]

Answer:

2. All the naturally occurring isotopes of Mg.

Explanation:

You want to know the atomic mass of the magnesium you use in the lab. That’s “natural” magnesium. So, you must use the weighted average of all the naturally occurring isotopes in natural Mg.

1. and 3. are wrong. You won’t get the correct mass for natural Mg if you use only the artificial isotopes for your calculation.

4. is wrong. You must use all the naturally occurring isotopes. The two most abundant isotopes of Mg account for only 90 % of the atoms. If you ignore the other 10 %, your calculation will be wrong.

6 0

3 years ago

To answer this question, you may need access to the periodic table of elements.

OleMash [197]

Answer:

b.) Br and Br

Explanation:

A covalent bond occurs when electrons are shared between two atoms causing them to form a bond.

A "pure" covalent bond refers to a nonpolar covalent bond. In these bonds, the electrons are shared equally between two atoms as a result of the absence of an (or very small) electronegativity difference. The purest covalent bond would therefore be between two atoms of the same electronegativity. Two bromines (Br) have the same electronegativity, thus making it the purest covalent bond.

Polar covalent bonds occur when electrons are shared unequally between two atoms. There is a larger electronegativity difference between the two atoms, but not large enough to classify the bonds as ionic. In this case, a.) and c.) are polar covalent bonds and d.) is an ionic bond.

7 0

1 year ago

Applications of chemistry in medical field

OLga [1]

Answer:

Explanation:

Drug for the treatment of disease. Chemistry contributes to the preparation and use of materials for surgery (sutures, artificial skin, and sterile materials). ...

Surgical procedure. ...

Blood samples for laboratory testing. ...

Blood glucose testing device.

6 0

3 years ago

An element is a pure substance. It can not easily be broken down into parts by physical means.

liberstina [14]

Answer: An element is a pure substance. It can not easily be broken down into parts by physical means.

A)True

B)False

The answer is true. 

7 0

4 years ago

How many moles of oxygen atoms are present in 30.5 grams of hydrogen peroxide (h2o2)?

Pepsi [2]

1.8 moles of oxygen atoms are present in 30.5 grams of hydrogen peroxide.

Explanation:

First we have to convert the given weight of hydrogen peroxide to molar mass of hydrogen peroxide. So for this, we have to divide the given weight with the molecular mass of hydrogen peroxide.

$\text {Molecular mass of } \mathrm{H}_{2} \mathrm{O}_{2}=(2 \times 1)+(2 \times 16)=2+32=34 \mathrm{g}$

So,

$\text {Molar mass of } \mathrm{H}_{2} \mathrm{O}_{2}=\frac{30.5}{34}=0.90 \text { moles of } \mathrm{H}_{2} \mathrm{O}_{2}$

Second step, in this moles, 2 molecules of oxygen are present. Thus 1 mole of Hydrogen peroxide consists of 2 moles of oxygen. Then,

$0.90 moles of $\mathrm{H}_{2} \mathrm{O}_{2}=2 \times 0.90=1.8$ moles of oxygen$

So, 30.5 grams of hydrogen peroxide consists of 1.8 moles of oxygen.

4 0

3 years ago