All categories

3 years ago

An atom has an atomic number of 12 and a mass number of 25. How many neutrons does the atom have?

1 answer:

6 0

Simple. The atomic number is the number of protons (12) and the mass number is the number of neutrons and protons combined. So you'd subtract 12 from 25 (25-12=) and that'd get you 13 as your answer. If you need to find the number of electrons, it'll be the same as the number of protons unless it has a certain charge and if it does, if it's positive it has more protons (+) than electrons (-), if it is negative it has more electrons (- negatively charged) than protons (+ positively charged)

You might be interested in

Which row probably contains the largest atoms on the periodic table?

svp [43]

The last row going across

7 0

3 years ago

2. Matt went to his friend’s party. He ate a big meal and drank a keg of beer. He felt heartburn after the meal and took Tums to

evablogger [386]

Answer:

390.85mL

Explanation:

Step 1:

Data obtained from the question.

Initial pressure (P1) = 780 torr

Initial volume (V1) = 400mL

Initial temperature (T1) = 40°C = 40°C + 273 = 313K

Final temperature (T2) = 25°C = 25°C + 273 = 298K

Final pressure (P2) = 1 atm = 760torr

Final volume (V2) =?

Step 2:

Determination of the final volume i.e the volume of the gas outside Matt's body.

The volume of the gas outside Matt's body can be obtained by using the general gas equation as shown below:

P1V1/T1 = P2V2/T2

780 x 400/313 = 760 x V2 /298

Cross multiply to express in linear form

313 x 760 x V2 = 780 x 400 x 298

Divide both side by 313 x 760

V2 = (780 x 400 x 298) /(313 x 760)

V2 = 390.85mL

Therefore, the volume of the gas outside Matt's body is 390.85mL

3 0

3 years ago

All of the statements describe hydrogen bonds EXCEPT: a. Hydrogen bonds account for the anomalously high boiling point of water.

Mamont248 [21]

Answer:

The correct option is e

Explanation:

Hydrogen bond is an intermolecular interaction/bonding that are formed between an electronegative atom (such as nitrogen, oxygen and fluorine) and a hydrogen atom. They are weak intermolecular bonds compared to covalent bonds but account for the high boiling point of water because of the strong hydrogen bond presence between the water molecules. Water molecules form hydrogen bonds between each other; since an oxygen atom (in a water molecule) has two lone pairs on it's outermost shell, it forms an hydrogen bond with two hydrogen atoms of other water molecule. Due to the fluidity of liquid water molecules, hydrogen bonds keep getting broken (although recreated/formed almost immediately), hence, individual hydrogen bonds in liquid water does not exist for long.

In the explanation above, it was stated that the strength of the hydrogen bond in water is the reason for it's high boiling point. The atoms in a water molecule are bent NOT linear hence the strength of hydrogen bond does not depend on the linearity of the atoms involved in the bond.

3 0

3 years ago

An acid with the general formula RCOOH is used to make a 0.10 M solution in water. The pH of this acid solution is measured as 3

Sati [7]

Answer:

0.159 \%

Explanation:

The acid will dissociate according to the reaction shown below:-

$RCOOH + H_2O\rightleftharpoons RCOO^- + H_3O^+$

Given that, pH=3.8

The concentration of can be determined from the expression fo pH as:-

pH = - log $[H^+]$

3.8 = - log $[H^+]$

$[H^+]$ = $1.59\times 10^{-4}\ M$

The initial concentration of RCOOH was 0.10 M, then the percent dissociation was- calculated as shown below:-

$\% \ dissociation=\frac{1.59\times 10^{-4}}{0.10}\times 100=0.159\ \%$

3 0

2 years ago

How many millimeters are there in 5.12 x 10^5

Anton [14]

Answer:

5.12x10¹¹ millimeters

Explanation:

Milli is a prefix used in science and engineering to decribe the number as the exponent x10⁻³. In the prefix kilo, the number is at the exponent x10³.

5.12x10⁵ kilometers are:

5.12x10⁵ kilometers * (1000m / 1km) = 5.12x10⁸ meters

5.12x10² meters * (1m / 1000millimeters) = 5.12x10¹¹ millimeters

8 0

3 years ago