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4 years ago

How to identify the number of protons neutrons and electrons and mass number?

1 answer:

5 0

1. Look at the atomic number of the element(located in upper left corner of the element box).This number represent the number of protons of the element.In same of the elements the number of electrons and protons are the same. in other (negative) you have to calculate
2. Look at the atomical mass( located underneath the element, which is a sum of neutrons and protons.Round the mass to the whole number and substract the atomic number. That will be number of neutrons.

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5. Which of these common substances is a

Oksana_A [137]

Oxygen is the correct answer.

7 0

3 years ago

1. When 50.0 mL of water at 80.0°C was mixed with 50.0 mL of water in a calorimeter at

ddd [48]

Answer:

The heat capacity of the calorimeter is 5.11 J/g°C

Explanation:

Step 1: Given data

50.0 mL of water with temperature of 80.0 °C

Specific heat capacity of water = 4.184 J/g°C

Consider the density of water = 1g/mL

50.0 mL of water in a calorimeter at 20.0 °C

Final temperature = 47.0 °C

Step 2: Calculate specific heat capacity of the water in calorimeter

Q = Q(cal) + Q(water)

Q(cal) = mass * C(cal) * ΔT

Qwater = mass * Cwater * ΔT

Qcal = -Qwater

mass(cal) * C(cal) * ΔT(cal) = mass(water) * C(water) * ΔT(water)

50 grams * C(cal) * (47.0 - 20.0) =- 50grams * 4.184 J/g°C * (47-80)

1350 * C(cal) = 6903.6

C(cal) = 5.11 J/g°C

The heat capacity of the calorimeter is 5.11 J/g°C

8 0

3 years ago

A sample of oxygen gas (O2) has a volume of 7.51 L at a temperature of 19°C and a pressure of 1.38 atm. Calculate the moles of O

Maslowich

Answer: 0.43molO₂

Explanation:

The ideal gas law for moles is $n=\frac{PV}{RT}$ . If you did not know, R is the ideal gas constant, $0.0821\frac{L*atm}{mol*K}$ .

Since the temperature must be in Kelvin, we must convert our given temperature from ℃ to K. $19C+273=292K$

Now that we have the temperature converted to Kelvin, we can plug in our information to the ideal gas law for the number of moles.

$n=\frac{PV}{RT}$

$n=\frac{1.38atm*7.51L}{0.0821\frac{L*atm}{mol*K} *292K} =0.43molO_{2}$

$n=0.43molO_{2}$

Therefore, the number of moles is 0.43molO₂.

I hope this helps! Pls mark brainliest!! :)

8 0

2 years ago

What substance is a combination of different atoms

MrMuchimi

I'm not suree.. is his science?

7 0

4 years ago

Read 2 more answers

Predict the splitting pattern for each of the labeled hydrogens in the following molecules. Assume that all coupling constants a

Ghella [55]

Complete Question

The complete question is shown on the first uploaded image

Answer:

a) Splitting pattern for Ha= 2+1 , Triplet

For Proton Hb and Hc both are equivalent to each other. non equivalent protons n= 3

Splitting pattern for Hb and Hc= 3+1 , Quartet

For Proton Hd, number of non equivalent protons n= 0

Splitting pattern for Hd= 0+1 , Singlet

b) Splitting pattern for Ha= 2+1 , Triplet

For Proton Hb and Hc both are equivalent to each other. non equivalent protons n= 3

Splitting pattern for Hb and Hc= 3+1 , Quartet

For Proton Hd, number of non equivalent protons n= 0

Splitting pattern for Hd= 0+1 , Singlet

c) The IUPAC name is Butan-2-ol

Explanation:

Considering the first question the rule used for prediction of splitting pattern is n+1 (Pascal's Triangle rule), where n is number of H atom on the adjacent carbon which are non equivalent.

According to that for molecule 1 as shown on the second uploaded image

For Proton Ha, number of non equivalent protons n= 2

Splitting pattern for Ha= 2+1 , Triplet

For Proton Hb and Hc both are equivalent to each other. non equivalent protons n= 3

Splitting pattern for Hb and Hc= 3+1 , Quartet

For Proton Hd, number of non equivalent protons n= 0

Splitting pattern for Hd= 0+1 , Singlet

Considering the second question for Molecule 2 as shown on the third uploaded image

For Proton Ha, number of non equivalent protons n= 1

Splitting pattern for Ha= 1+1=2 , Doublet

For Proton Hb, number of non equivalent protons n= 3

Splitting pattern for Hb= 3+1=4 , Quartet

For Proton Hc, number of non equivalent protons n= 3

Splitting pattern for Hc= 3+1=4 , Quartet

For Proton Hd, number of non equivalent protons n= 1

Splitting pattern for Ha= 1+1=2 , Doublet

Considering the third question

The name of the given molecule is gotten according to longest carbon chain = 4 (Prefix 'Butan')

Functional group = -OH (Suffix 'ol') at C-2

The IUPAC name is Butan-2-ol

3 0

3 years ago