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jeka94
3 years ago
7

. Element X has a nucleon (mass) number of 19 and a proton (atomic) number of 9.

Chemistry
1 answer:
Marina86 [1]3 years ago
7 0

Answer:

C

Explanation:

it belong to that group as it needs 1 electron to be chemically stable

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List the sub-atomic particles in the order in which they were discovered and tell who discovered each one.
harkovskaia [24]
<span>Photons were the first sub-atomic particles detected, but not quite discovered as they could not be explained. Photons were first detected by Johann Wilhelm Ritter, Victor Schumann, and Winhelm Rontgen. The next, and first sub-atomic particle discovered, was the electron. The electron was discovered by J. J. Thompson in the late 1800s. The next two sub-atomic particle discoveries were the alpha particle and photon, discovered by Ernest Rutherford and Paul Villard respectively. Rutherford also discovered the proton and in 1932, James Chadwick discovered the neutron.</span>
7 0
3 years ago
A substance with a density of 2.70 g/mL occupies a volume of 21.3 mL. What is the mass of the sample? Report your answer in unit
katen-ka-za [31]
We know the formula of the density:
ρ =\frac{m}{V} ;
So the mass will be equal to:
m = ρ * V = 2.70  * 21.3 = 57,51 g = 57510 mg of substance.
So the answer is 57510.
7 0
3 years ago
In an experiment, students were given an unknown mineral. The unknown mineral was placed in 150 ml of water. Once in the water,
Dahasolnce [82]

Answer:

<h2>15 g/mL</h2>

Explanation:

The density of a substance can be found by using the formula

density =  \frac{mass}{volume}  \\

But from the question

volume = final volume of water - initial volume of water

volume = 165 - 150 = 15 mL

We have

density =  \frac{225}{15}  = 15 \\

We have the final answer as

<h3>15 g/mL</h3>

Hope this helps you

5 0
2 years ago
A hydrogen halide diffuses 1.49 times faster than HBr. This hydrogen halide is
marysya [2.9K]

To solve this problem, we must assume ideal gas behaviour so that we can use Graham’s law:

vA / vB = sqrt (MW_B / MW_A)

where,

<span>vA = speed of diffusion of A  (HBR)</span>

vB = speed of diffusion of B (unknown)

MW_B = molecular weight of B (unkown)

MW_A = molar weight of HBr = 80.91 amu

 

We know from the given that:

vA / vB = 1 / 1.49

 

So,

1/1.49 = sqrt (MW_B / 80.91)

MW_B = 36.44 g/mol

 

Since this unknown is also hydrogen halide, therefore this must be in the form of HX.

HX = 36.44 g/mol , therefore:

x = 35.44 g/mol

 

From the Periodic Table, Chlorine (Cl) has a molar mass of 35.44 g/mol. Therefore the hydrogen halide is:

HCl

6 0
3 years ago
What two things effect the amount of kinetic energy an object has?
marta [7]

Answer:

mass and speed

Explanation:

the motion of an object depends on how fast it's travelling and also how much mass it has

3 0
3 years ago
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