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2 years ago

PLEASE HURRY

Chemistry

1 answer:

ladessa [460]2 years ago

8 0

Answer:

C. Galactic disk

Explanation:

The galactic disk is a component of the spiral galaxies and consists of stellar and gaseous components as it forms a random motion with the circular objects that orbit around the galactic center.

The rotational curve in a milky way is similar to that of the rotation of the universal rotating disk and is evident by the dark matter in the galaxies.

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How is the preodictable arranged by atomic mass, coloms , and rows

bearhunter [10]

answer:an arrangement of elements in columns, based on a set of properties that repeat from row to row

Explanation:

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5 0

2 years ago

Read 2 more answers

If the same amount of heat is added to 25.0 g of each of the metals, which are all at the same initial temperature, which metal

AVprozaik [17]

Answer:

The bismuth sample.

Explanation:

The specific heat $c$ of a substance (might not be a metal) is the amount of heat required for heating a unit mass of this substance by unit temperature (e.g., $\rm 1\; ^{\circ}C$ .) The formula for specific heat is:

$\displaystyle c = \frac{Q}{m \cdot \Delta T}$ ,

where

$Q$ is the amount of heat supplied.
$m$ is the mass of the sample.
$\Delta T$ is the increase in temperature.

In this question, the value of $Q$ (amount of heat supplied to the metal) and $m$ (mass of the metal sample) are the same for all four metals. To find $\Delta T$ (change in temperature,) rearrange the equation:

$\displaystyle c \cdot \Delta T = \frac{Q}{m}$ ,

$\displaystyle \Delta T = \frac{Q}{c \cdot m}$ .

In other words, the change in temperature of the sample, $\Delta T$ can be expressed as a fraction. Additionally, the specific heat of sample, $c$ , is in the denominator of that fraction. Hence, the value of the fraction would be the largest for sample with the smallest specific heat.

Make sure that all the specific heat values are in the same unit. Find the one with the smallest specific heat: bismuth ( $\rm 0.123 \; J \cdot g\cdot \,^{\circ}C^{-1}$ .) That sample would have the greatest increase in temperature. Since all six samples started at the same temperature, the bismuth sample would also have the highest final temperature.

3 0

2 years ago

the valence electrons of an atom of which element would feel a smaller effective nuclear charge than the valence electrons of a

Dvinal [7]

D. Strontium is the right answer

5 0

3 years ago

Calculate the mole fraction of kbr (molar mass 119.00 g/mol) in a solution made by dissolving 0.30 g kbr in 0.400 l of H2O (d =

julia-pushkina [17]

The mole fraction of KBr in the solution is 0.0001

<h3>How to determine the mole of water</h3>

We'll begin by calculating the mass of the water. This can be obtained as follow:

Volume of water = 0.4 L = 0.4 × 1000 = 400 mL
Density of water = 1 g/mL
Mass of water =?

Density = mass / volume

1 = Mass of water / 400

Croiss multiply

Mass of water = 1 × 400

Mass of water = 400 g

Finally, we shall determine the mole of the water

Mass of water = 400 g
Molar mass of water = 18.02 g/mol
Mole of water = ?

Mole = mass / molar mass

Mole of water = 400 / 18.02

Mole of water = 22.2 moles

<h3>How to de terminethe mole of KBr</h3>

Mass of KBr = 0.3 g
Molar mass of KBr = 119 g/mol
Mole of KBr = ?

Mole = mass / molar mass

Mole of KBr = 0.3 / 119

Mole of KBr = 0.0025 mole

<h3>How to determine the mole fraction of KBr</h3>

Mole of KBr = 0.0025 mole
Mole of water = 22.2 moles
Total mole = 0.0025 + 22.2 = 22.2025 moles
Mole fraction of KBr =?

Mole fraction = mole / total mole

Mole fraction of KBr = 0.0025 / 22.2025

Mole fraction of KBr = 0.0001

Learn more about mole fraction:

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6 0

1 year ago

A weak bond called a ______ bond results from an attraction between a slightly positive region in a molecule and a slightly nega

tamaranim1 [39]

<u>Answer:</u> The weak bond having slightly positive region and a slightly negative region is polar covalent bond.

<u>Explanation:</u>

Covalent bond is defined as the bond which is formed by the sharing of electrons between the atoms. <u>For Example:</u> HCl, $CH_4$ etc..

They are of two types:

<u>Polar covalent bond:</u> This bond is formed when difference in electronegativity between the atoms is present. When atoms of different elements combine, it results in the formation of polar covalent bond.

In this bond, a dipole is created. More electropnegative atom will have a slight negative charge and less electronegative atom will have a slight positive charge. For Example: $CO_2,NO_2$ etc..

<u>Non-polar covalent bond:</u> This bond is formed when there is no difference in electronegativity between the atoms. When atoms of the same element combine, it results in the formation of non-polar covalent bond. For Example: $N_2,O_2$ etc..

Hence, the weak bond having slightly positive region and a slightly negative region is polar covalent bond.

7 0

2 years ago