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Viktor [21]
4 years ago
10

Please help! I’m on my last attempt

Chemistry
1 answer:
deff fn [24]4 years ago
6 0
First line: The atomic number is the whole number on the periodic table so atomic number 35 means the element is bromine. Thus the element symbol is Br. The atomic number is also the number of protons in the isotope so the number of protons is 35. The mass number is the sum of protons and neutrons in the isotope so the mass number is 35+46 or 81. The mass number gives you the top left number on the nuclear symbol (it will look the same as the one below it except the 79 is an 81). Lastly, the number of electrons is equal to the number of protons in a neutral atom so 35 electrons.
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A 48.3 mL sample of gas in a cylinder is warmed from 22 °C to
goldenfox [79]

Answer:

58.94 mL

Explanation:

V1 = 48.3 mL             V2 = v mL

T1 = 22 degree celsius OR 295 k         T2 = 87 degree celsius OR 360 k

We will use the gas equation:

PV = nRT

Since the Pressure (p) , number of moles (n) and the universal gas constant(R) are all constants in this given scenario,

we can say that

V / T = k , (where k is a constant)

Since this is the first case,

V1 / T1 = k --------------------(1)

For case 2:

Since we have the same constants, the equation will be the same

V / T = k (where k is the same constant from before)

V2 / T2 = k (Since this is the second case) ------------------(2)

From (1) and (2):

V1 / T1 = V2 / T2

Now, replacing the variables with the given values

48.3 / 295 = v / 360

v = 48.3*360 / 295

v = 58.94 mL

Therefore, the final volume of the gas is 58.94 mL

4 0
3 years ago
Explain why Ra is larger than Be. With 2 points.
igor_vitrenko [27]

Explanation:

<h2>Radium(Ra)=> </h2>

atomic number=88

<h2>BERYLLIUM (Be)=></h2>

atomic number =4

why is Ra larger than Be

<h3>1. since the atomic number of Ra is greater than Be, the number of electrons is more, which means there are more number of shells present in Ra than Be. </h3><h2>(atomic Radius)</h2>

<h2>2. the more the valence electron (excluding fully filled ones) the less is the nuclear attraction force</h2><h3>since Ra has more valence electron in its outermost shell, the nuclear attraction force is less which means that Ra 's size is greater than Be.</h3>

hope it helps:)

6 0
3 years ago
What elements comprise the largest portion of Earth's atmosphere?​
Mrrafil [7]

Answer:

Nitrogen and Oxygen make up 99% of the Earths atmosphere. Then Argon makes up the rest of the atmosphere.

3 0
3 years ago
The diffusion of substances within a solution tends to move those substances ________ their ________ gradient.
guajiro [1.7K]

What is diffusion?

The diffusion of substances within a solution tends to move those substances <u>down</u> their <u>concentration</u> gradient.

Aim of diffusion:

The movement of molecules along a concentration gradient is known as diffusion. It is a significant process that all living things go through. Diffusion facilitates the flow of materials into and out of cells. Until the concentration is the same everywhere, the molecules travel from a location of higher concentration to a region of lower concentration.

Diffusion occurs in gases and liquids because random molecular movement is possible.

Types of diffusion:

Simple diffusion and facilitated diffusion are the two primary categories of diffusion.

  • Simple diffusion: An action where the substance passes across a semipermeable barrier or solution without the aid of transport proteins. For instance, bacteria use simple diffusion to transport minute nutrients, water, and oxygen into the cytoplasm.
  • Facilitated diffusion: It is the passive transfer of molecules from the area of higher concentration to the area of lower concentration across the cell membrane using a carrier molecule.

The main aim of diffusion is to arrive at an equilibrium state. When the amount of the particles is uniformly distributed or constant throughout a solution, it is said to be in equilibrium.

Learn more about diffusion here,

brainly.com/question/14852229

#SPJ4

3 0
2 years ago
Which of the following is a molecule but
Oksana_A [137]

Answer:

CO2

Explanation:

All of the other options are elements found on the periodic table but Carbon Dioxide are two elements.

5 0
3 years ago
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