help me plz, ASAP . (25 points)

Answer:

B,D,E

Explanation:

Answer:

kilo gram

Explanation:

kilogram(kg)

Answer:

Kilogram (Kg).......

Answer:

The charge of an element is equal to the number of protons minus the number of electrons. The number of protons is equal to the atomic number of the element given in the periodic table. The number of electrons is equal to the atomic number minus the charge of the atom.

Explanation:

Answer:

The kinetic energy of the two stones is 320 J

Explanation:

Kinetic energy is the energy that a body possesses due to its movement. So it is the capacity or work that allows an object to go from being at rest, or still, to moving at a certain speed.

In other words, the kinetic energy of an object is that which is produced due to its motion and depends on its mass and velocity as follows:

[tex]Ec=\frac{1}{2} *m*v^{2}[/tex]

where the kinetic energy Ec is measured in joules (J), the mass m is measured in kilograms (kg) and the velocity v in meters/second (m/s).

In this case you know that a 20 kg curling stone is sliding in a positive direction at 4 m/s. So:

Replacing you have:

[tex]Ec_{1} =\frac{1}{2} *20 kg*(4\frac{m}{s}) ^{2}[/tex]

Ec₁= 160 J

A second curling stone slides at the same speed but in the opposite direction. So:

Replacing you have:

[tex]Ec_{2} =\frac{1}{2} *20 kg*(-4\frac{m}{s}) ^{2}[/tex]

Ec₂= 160 J

The kinetic energy of the two stones is calculated as:

Ec= Ec₁ + Ec₂

Ec= 160 J + 160 J

Ec= 320 J

The kinetic energy of the two stones is 320 J

Answer:

c) Wash your hands

Explanation:

A laboratory or most popularly called as lab is a place or facility which provides controlled conditions where some educational research, scientific studies, experiments, testings, can be performed. The place is equipped with sophisticated machines, test samples, hazardous chemicals, instruments  etc.

The university or college lab, there is a incharge of the lab called as the lab instructor who is responsible for all the belongings of the lab and the safety of the experimenter or the students.

After performing some experiments or testing with some chemicals, the last and the most important thing we need to do is to wash our hand with soap or hand wash. it is very important because we touch many test samples and hazardous chemical which might go inside our mouth or eyes accidentally, which might be harmful to us.

So, it is important to wash our hand at last before leaving the lab.

Answer:

41.17

Explanation:

n Zn =  mass / m.wt

      = 8.75 /(65.4) = 0.1338 mole

n HCL = ( from the balanced equation )

     2HCL                  Zn

          2mole   → 1  mole

          x  mole     →             0.1338mole

     n HCL = .268 mole

M= mole/liter

6.50= 0.268/x

so u have0.04117  liter = 41.17 ml

Mole measure the number of elementary entities of a given substance that are present in a given sample. Therefore, 41.17 ml of 6.50 M HCl(aq) are required to react with 8.75 g Zn(s).

The SI unit of amount of substance in chemistry is mole. The mole is used to measure the quantity or amount of substance. We know one mole of any element contains 6.022×10²³ atoms which is also called Avogadro number.

Mathematically,

number of moles of zinc=  mass / molecular mass

                                       = 8.75 /(65.4) = 0.1338 mole

number of moles of HCl ( from the balanced equation )

2 moles of HCl reacts with one mole of Zn

number of moles of HCl = 2×0.1338 =0.268 mole

Molarity = number of mole of HCl/volume occupied by solution

6.50= 0.268/volume

Volume of HCl = 41.17 ml

Therefore, 41.17 ml of 6.50 M HCl(aq) are required to react with 8.75 g Zn(s).

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Answer:

Explanation:

When an atom loses electron(s) it will lose some of its negative charge and so becomes positively charged. A positive ion is formed where an atom has more protons than electrons. In the opposite case when an atom gains electron(s) it becomes negatively charged (more electrons than protons)

and plzs do not hate

The charge of chromium after losing 4 electrons is +2.

Ions are two or more charged particles that make up ionic compounds. Electrostatic attraction keeps the ions together (in the solid phase) despite their opposing charges. Cations are positively charged ions, whereas anions are negatively charged ions. Many factors make ionic molecules significant.

They act as electrolytes for batteries and conduct electricity when dissolved in water. They could form a strong bond with other charged particles, such as those found in environmental samples or the human body. They find use in fireworks, flares, and lights because they are frequently multicolored when burned. The list is endless!

Studying the nomenclature used to give ionic compounds distinctive names is a good method to become familiar with and exposed to them. You will learn how to properly explain the identification of substances in language by converting from a chemical formula to a name—a highly essential problem as the diversity and complexity of known compounds keeps growing!

Therefore, the charge on chromium after losing 4 electrons is +2.

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Answer:

d = 16.96 g/mL

Explanation:

Given that,

Initial water level in graduated cylinder is 47 mL and final water level is 48.35 mL.

The weight of the neclace is 22.89 g.\

We need to find the volume of the necklace. We know that, density equals mass per unit volume. So,

[tex]d=\dfrac{m}{V_f-V_i}\\\\d=\dfrac{22.89\ g}{(48.35-47)\ mL}\\\\d=16.96\ g/mL[/tex]'

Hence, the density of Terry’s necklace is 16.96 g/mL.

Answer:

A

Explanation:

The new mine means the supply is high and the price is low, so she can afford the necklace

Review your instructions

Answer:

it might be able to get a heading to a earth

contaminants from your community can flow through runoff into a river basin.

Contaminants from your community affect a river basin that is miles away could runoff can carry pollutants from your neighborhood into a river basin.

Community is defined as a social community that shares characteristics like geography, rules, beliefs, values, or identities.  Community is important because they are frequently a significant source of social connection and a sense of belonging, strong communities are essential. Living a fulfilling life requires being a part of a group of people who share similar attitudes, values, and aspirations.

Contaminants are defined as a substance that, whether unintentionally or on purpose introduced to air, water, soil, or food, becomes detrimental to humans or other living things on a biological, chemical, physical, or radiological level. Chemical, physical, and biological pollution are the three different types.

Thus, contaminants from your community affect a river basin that is miles away could runoff can carry pollutants from your neighborhood into a river basin.

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Answer:

its the 3rd option.

the molecules move from region of higher concentration to a region of lower concentration.

Explanation:

please do give me brainliest if this helped you.

thank you and have a great day :D

Answer:

The molecules move from areas of high concentration to low concentration

Explanation:

Answer:

because acids come from various chemical substances

Given :

Mass of methanol ( [tex]CH_3OH[/tex] ) , m = 5 kg = 5000 g .

Volume of water , [tex]V=2\ m^3=2000\ L[/tex] .

To Find :

Molecules of methanol per liter of water .

Solution :

Moles of methanol , [tex]n=\dfrac{5000}{32}=156.25\ mol[/tex] .

We know , 1 mole of a substance contains [tex]6.022\times 10^{23}\ mol^{-1}[/tex] .

So , total number of molecules :

[tex]M=156.25\times 6.022\times 10^{23}\\\\M=9.41\times 10^{25}[/tex]

Number of molecules per liter :

[tex]\dfrac{9.41\times 10^{25}}{2000}\\\\4.705\times 10^{22}[/tex]

Hence , this is the required solution .

Answer:

It doesn't have measure marks on it.

Answer:

Volume = 30cm³

Explanation:

A block is a geometrical figure and its volume, -look at the figure-, follows the equation:

Volume = Width*Length*Height

As the measurements of the block are 5.00cm, 3.00cm and 2.00cm, the volume is:

Volume = 5.00cm*2.00cm*3.00cm

Answer:

Option B. 28.5 amu

Explanation:

The following data were obtained from the question:

Isotope A:

Mass of A = 28.0 amu

Abundance (A%) = 14.0%

Isotope B:

Mass of B = 29.0 amu

Abundance (B%) = 66.0%

Isotope C:

Mass of C = 27.4 amu

Abundance (C%) = 20.0%

Atomic mass of element X =.?

The atomic mass of element X can be obtained by using the following formula:

Atomic mass = [(Mass of A × A%)/100] + [(Mass of B × B%)/100] + [(Mass of C × C%)/100]

Atomic mass of Element X = [(28 × 14)/100] + [(29 × 66)/100] + [(27.4 × 20)/100]

= 3.92 + 19.14 + 5.48

= 28.54 ≈ 28.5 amu

Therefore, the atomic mass of Element X is 28.5 amu

Answer:

For hydrogen. H

Explanation:

Atomic number is 1

Proton number is 1

Mass number is 2

Neutron number is 1

Answer:

108.5

Explanation:

half of 150 is 75 and half of that is 32.5. Add that to 75 and you'll get your answer

112.5 g of iron is present in the alloy.

From the question given above, the following data were obtained:

Percentage of iron (Fe) = 75%

Percentage of other elements = 25%

Mass of the alloy = 150 g

The mass of the iron present in the alloy can be obtained as follow:

[tex]Percentage = \frac{mass of element }{total mass }\\\\[/tex]

75% = [tex]\frac{mass of Fe}{150}[/tex]

[tex]0.75 = \frac{mass of Fe}{150}\\\\[/tex]

Cross multiply

Mass of Fe = 0.75 × 150

Therefore, 112.5 g of iron is present in the alloy.

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Answer:

The CORRECT answer is Solution

Explanation:

Since a Colloid is a liquid like substance that cannot be removed from other solids the only possible choice would be a Solution. becuase with a solution you can drain the solution and still get the beans.

Answer:

titanium and potassium

Explanation:

Answer: geranium and krypton

Explanation: hope this helps

Answer:

A is the ans

Explanation:

they repel each

Answer:

3.6

Explanation:

3.6 is only 0.1 away from 3.5

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Answer:

line graph

Explanation:

The type of graph would be used to display the data is line graph.

Graph is defined as a visual representation, such as a picture or diagram, that shows information or values in a structured way.  The graph's goal is to visually represent numerical data so that it can be quickly, simply, and clearly understood. As a result, graphs are visual displays of data.

Although a graphical display is easier to understand, data can also be presented as a table. For this kind of data, a line graph will be used. This will show more clearly how the temperature of the water fluctuates over the course of two hours. Time is an independent variable, whereas temperature is a dependent variable.

Thus, the type of graph would be used to display the data is line graph.

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Answer:303.15

Explanation:

ions because it’s still the same element, however the charge has changed