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spayn [35]
2 years ago
7

What is the atomic number for an element whose mass number is 78,

Chemistry
2 answers:
Ann [662]2 years ago
5 0

Answer:

protons = atomic numbermass number = protons + neutronsatomic number = mass number - neutrons = 78-38 = 40

Explanation:

murzikaleks [220]2 years ago
4 0

Answer:

48

Explanation:

i took the test lolll

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How many moles of methane occupy a volume of 2.00 l at 50.0°c and 0.500 atm answer?
Sauron [17]
Data Given:
                  Pressure  =  P  =  0.5 atm
 
                  Volume  =  V  =  2.0 L

                  Temperature  =  T  =  50 °C + 273  =  323 K

                  Moles  =  n  =  ?

Solution:
              Let suppose the gas is acting Ideally, Then According to Ideal Gas Equation.

                              P V  =  n R T
Solving for n,
                              n  =  P V / R T

Putting Values,
                             n  =  (0.5 atm × 2.0 L) ÷ (0.0821 atm.L.mol⁻¹.K⁻¹ × 323 K)

                             n  =  0.0377 mol
5 0
2 years ago
Word equation of almininum reaction with oxygen​
zheka24 [161]

Answer:

Aluminium + oxygen = almininum oxide

Hope it helps!! Please make me brainliest...

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4 0
3 years ago
A car traveling at a speed of 30.0 m/s encounters an emergency and comes to a complete stop in 7.5 seconds? What is the cars acc
Marianna [84]

Answer:

The acceleration is: 4m/s^2

Explanation:

Given

u = 30.0m/s --- The initial velocity

t = 7.5s --- time

v = 0m/s -- The final velocity

Required

Determine the acceleration

To do this, we make use of the first equation of motion

v = u - at

We used negative because the car was coming to stop.

This gives:

0 = 30 - 7.5 * a

0 = 30 - 7.5a

Collect like terms

7.5a = 30

Solve for a

a = \frac{30}{7.5}

a = 4m/s^2

6 0
3 years ago
How many grams in 82 moles of CO2
Tems11 [23]

44.0 g/mol

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6 0
3 years ago
If an atom contains one electron and one proton,will it carry any charge or not​
sertanlavr [38]

Answer:

no it will have no charge...it would be electrically neutral! because the number of protons and electrons are equal!

8 0
3 years ago
Read 2 more answers
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