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Artyom0805 [142]
3 years ago
9

1. An atom of an elephant has atomic mass of 39 and has number of neutrons as 20 calculate protons number.

Chemistry
1 answer:
r-ruslan [8.4K]3 years ago
5 0

Answer:

See Explanation

Explanation:

1) Let us recall that;

Mass number = number of protons + number of neutrons

Where;

Number of protons = ?

Number of neutrons =20

Mass number =39

Number of protons = mass number - number of neutrons

Mass of protons =39 - 20= 19 protons

2) Atomic number = 13

Number of neutrons =14

Then the mass number =13 +14 =27

The symbol of the element is 27X13

The number of protons= the number of electrons =13

The atomic number is the same as the proton number =13

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1) List the number of protons, neutrons, and electrons in Carbon-13.
ser-zykov [4K]
1) Carbon-13: 
                      Proton-6     Neutron-7       Electron-6

2)Atomic mass of element X:
   (55*10+56*20+57*70)/100=56.6
4 0
3 years ago
If the specific heat of a solution is 4.18 J/goC, and you have 296 mL (1.03 g/mL) which increases in temperature by 6.9 degrees,
Sergeu [11.5K]

Answer:

Q = 8.8 kJ

Explanation:

Step 1: Data given

The specific heat of a solution = 4.18 J/g°C

Volume = 296 mL

Density = 1.03 g/mL

The temperature increases with 6.9 °C

Step 2: Calculate the mass of the solution

mass = density * volume

mass = 1.03 g/mL * 296 mL

mass = 304.88 grams

Step 3: Calculate the heat

Q = m*c*ΔT

⇒ with Q = the heat in Joules = TO BE DETERMINED

⇒ with m = the mass of the solution = 304.88 grams

⇒ with c = the specific heat of the solution = 4.18 J/g°C

⇒ with ΔT = the change in temperature = 6.9 °C

Q = 304.88 g * 4.18 J/g°c * 6.9 °C

Q = 8793.3 J = 8.8 kJ

Q = 8.8 kJ

8 0
3 years ago
Calculate the amount of heat, in kilojoules, required to turn solid ammonia at -78 degrees Celsius to gaseous ammonia at standar
zhuklara [117]

Answer:

132

Explanation:

3 0
3 years ago
One sphere has a radions of 181 cm, another has a radius of 5.01 cm. What is the difference in volume (in cubic centimeters) bet
PSYCHO15rus [73]

Answer:

2.4*10^{7}cm^{3}

Explanation:

First you should calculate the volume of a big sphere,so:

V_{big}=\frac{4}{3}\pi r^{3}

V_{big}=\frac{4}{3}\pi (181cm)^{3}

V_{big}=2.4*10^{7}cm^{3}

Then you calculate the volume of a small spehre, so:

V_{small}=\frac{4}{3}\pi r^{3}

V_{small}=\frac{4}{3}\pi (5.01cm)^{3}

V_{small}=5.3*10^{2}cm^{3}

Finally you subtract the two quantities:

V_{big}-V_{small}=2.4*10^{7}cm^{3}-5.3*10^{2}cm^{3}

V_{big}-V_{small}=2.4*10^{7}cm^{3}

5 0
3 years ago
Complete and balance the following redox reaction in basic solution
inn [45]

Answer:

balanced in ACID not BASE

Cr2O7^2-(aq) +3Hg(l) +14 H^1+ ----> 3Hg^2+ + 2Cr^3+(aq) + 7H2O

Answer

Cr2O7^2-(aq) +3Hg(l) +14 H^1+ ----> 3Hg^2+ + 2Cr^3+(aq) + 7H2O

Explanation:

Cr2O7^2-(aq) + Hg(l) ----> Hg^2+(aqH) + Cr^3+(aq)

add H^1+ (acid) to capture the O and make 7 water molecules

Cr2O7^2-(aq) + Hg(l) + H^1+ ----> Hg^2+(aqH) + Cr^3+(aq) + 7H2O

Cr goes from +6 to +3 by gaining 3 e

Hg goes from 0 to +2 by losing 2 e

we need 3 Hg for every 2 Cr

so

Cr2O7^2-(aq) +3Hg(l) +14 H^1+ ----> 3Hg^2+ + 2Cr^3+(aq) + 7H2O

2 Cr on the right and left

Net 12 positive charges on the right and the left

3 Hg on the right and left

14 H on the right and left

the equation is balanced

we cannot balance the equation in a basic solution with OH^1-

we have plenty of O in the dichromate ion. we need to convert it to water which take free H^1+ from the acid

8 0
3 years ago
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