I need help working these

Answer:

electrical --> light

Explanation:

Answer:

[(x-37.5)/x]*100%

62.5%  (assuming the original sample weighs 100.0g)

Explanation:

Let's say that the original sample is x

Mass of I-125 which has decayed: x-37.5

Percentage of decayed mass: [(x-37.5)/x]*100%

Please recheck, for this may not be the correct answer

Answer:

Manganese

Explanation:

The electronic configuration of the atom is:

         1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁵

The powers in this configuration is the number of electrons in each orbital:

2 + 2 + 6 + 2 + 6 + 2 + 5  = 25

The compound has 25 electrons and it is Manganese

The electron configuration 1s22s22p63s23p64s23d5 corresponds to the element manganese (Mn).

In the electron configuration provided:

1s2 represents the filling of the 1s subshell with two electrons.

2s2 represents the filling of the 2s subshell with two electrons.

2p6 represents the filling of the 2p subshell with six electrons.

3s2 represents the filling of the 3s subshell with two electrons.

3p6 represents the filling of the 3p subshell with six electrons.

4s2 represents the filling of the 4s subshell with two electrons.

3d5 represents the filling of the 3d subshell with five electrons.

Based on this electron configuration, we can correctly identify the element as manganese (Mn), which has an atomic number of 25.

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Answer:

Weathering involves the use of water and or wind to wear down the environment. The sand dunes were most likely carried by wind to form them and form its shape. Erosion most likely took away parts of the sand to make the sand dune. Deposition most likely deposited sand to the area.

Explanation:

If you possibly want a better explanation, try looking it up :).

#teamtrees #WAP (Water And Plant)

Answer:

Fluorine gas reacts violently with water to produce hydrogen fluoride and ozone according to the following unbalanced equation. How many moles of o, are created assuming STP conditions are in effect, given

Explanation:

3

Answer:

[tex]Distance = 40km[/tex]

Explanation:

Given

[tex]Speed = 80km/hr[/tex]

[tex]Time = 0.5hr[/tex]

Required

Determine the distance covered

Distance is calculated as:

[tex]Distance = Speed * Time[/tex]

Substitute values for Speed and Time

[tex]Distance = 80km/hr * 0.5hr[/tex]

[tex]Distance = 80km * 0.5[/tex]

[tex]Distance = 40km[/tex]

Hence, you travelled 40km

Answer:

4.00L

Explanation:

Using Charle's law, which have the following equation:

V1/T1 = V2/T2

Where;

V1 = initial volume (litres)

T1 = initial temperature (Kelvin)

V2 = final volume (litres)

T2 = final temperature (Kelvin)

According to the information provided, T1 = 275K, T2 = 400K, V1 = ?, V2 = 5.82L

Hence, using the formula;

V1/275 = 5.82/400

400 × V1 = 275 × 5.82

400V1 = 1600.5

V1 = 1600.5 ÷ 400

V1 = 4.001

Therefore, volume of the gas before it is heated is 4.00L

Answer:

percent yield = 80.7%

Theoretical yield of silver sulfide = 30.975 g

Actual yield  = 25 g

Explanation:

Given data:

Mass of silver = 27 g

Mass of silver sulfide formed = 25 g

Theoretical yield of silver sulfide = ?

Actual yield = ?

Percent yield = ?

Solution:

Chemical equation:

2Ag + S   →     Ag₂S

Number of moles of Ag:

Number of moles = mass/molar mass

Molar mass of silver = 107.8 g/mol

Number of moles = 27 g/ 107.8 g/mol

Number of moles = 0.25 mol

Now we will compare the moles of silver with silver sulfide.

               Ag         :       Ag₂S

               2            :         1

              0.25        :      1/2×0.25 = 0.125 mol

Theoretical yield of silver sulfide:

Mass = number of moles × molar mass

Mass = 0.125 mol ×  247.8 g/mol

Mass = 30.975 g

Actual yield is given in question = 25 g

Percent yield:

Percent yield = (actual yield / theoretical yield) × 100

Percent yield = (25 g/ 30.975 g ) × 100

percent yield = 80.7%

Answer:

no it should not that place is historical and so they should make where u can visit but protect it as a historical landmark

Answer:

Dissolving sugar in water, burning paper, and melting gold are all chemical changes

Explanation:

The action cannot be reversed, or undone. Therefore it is a chemical change.

Boiling water is a physical change.

1.999 mol gas

Math

Pre-Algebra

Order of Operations: BPEMDAS

Chemistry

Atomic Structure

Step 1: Define

1.204 × 10²⁴ atoms gas

Step 2: Identify Conversions

Avogadro's Number

Step 3: Convert

Step 4: Check

Follow sig fig rules and round. We are given 4 sig figs.

1.99934 mol gas ≈ 1.999 mol gas

Answer:

The first question is option 2

and the second question in option 1

Explanation:

Answer:

I belive 2 of them are Bromine and Mercury there are more then just 2 but im not the best at science sorry.

Explanation:

Answer:

it is 1,4

Explanation:

Just took the test hope you get it right. c:

Answer:

It is made of numbers

Explanation:

Found the hard way.

Answer:

There are 2 atoms of Oxygen (O) present in SO2 therefore it's atomicity is 2

Answer: Strontium has 219 pm

Iodine has 115 pm

Explanation: So the answer is Sr-Strontium

Answer:

it should be the stamen but to be sure look up the structure of a flower

Answer:

a) high pressure

that is the answer i got, but wait for a few more answers before you write the answer

Answer:

The pan on the bottom right with the arrows pointing up.

Explanation:

conduction is the transfer of heat through touching surfaces, so when you place the pan on a hot stove, the heat heats up the bottom of the pan, and then the water in it.

The transfer of energy between systems through work is the expansion of gas in a steam engine. Therefore, the second diagram in the second row shows the correct direction of flow of heat.

Energy transfer is a phenomenon in which energy transfer from one matter to another matter. Energy can be transferred in two forms that are by doing work or by transferring heat.

Heat can be transferred by three ways conduction, convention and radiation. In conduction, when two object are in direct contact, transfer of molecules takes place. When heat flow through touching surfaces is called conduction. Heat flows in the upward direction from bottom in a pan.

Therefore, the second diagram in the second row shows the correct direction of flow of heat.

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Explanation:

Different heating process affect the microstructure of the steel in different ways. Thus, imparting different properties to the steel. For example, annealing is done is done to impart softness to steel, hardening is done to hardened the steel( eg: carburizing, nitriding, cyaniding) whereas tempering is done to improve the ductility of the steel.

Steel mainly contains iron and carbon. This percentage of carbon and iron decides the property of the steel. It is the % of carbon which is altered in different heating process that to obtained the desire microstructure in steel.

Answer:

precipitation

Explanation:

gravity pulls down rain

Answer:

b

Explanation:

The balanced equation for the synthesis of sulfuric acid is SO₃ + H₂O → H₂SO₄.

Those chemical reactions in which amount of species are present in equal amount on left side as well as on right side of the chemical reaction.

Sulphuric acid is formed by the combination of water with the sulphur trioxide, chemically it is represented as:
SO₃ + H₂O → H₂SO₄

Above reaction is balanced as each element is present in same amount on both side.

Hence, option (b) is correct.

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Answer:

A or B they do it for different reasons.

Explanation:

Answer:118

Explanation: it’s right

Answer:

118 elements

Hope that helps

Answer:

The number of formula units in 3.81 g of potassium chloride (KCl) is approximately 3.08 × 10²²

Explanation:

The given parameters is as follows;

The mass of potassium chloride produced in the chemical reaction (KCl) = 3.81 g

The required information = The number of formula units of potassium chloride (KCl)

The Molar Mass of KCl = 74.5513 g/mol

[tex]The \ number \ of \ moles \ of \ a \ substance, n = \dfrac{The \ mass \ of \ the substance}{The \ Molar \ Mass \ of \ the \ substance}[/tex]

Therefore, we have;

[tex]The \ number \ of \ moles \ of \ KCl= \dfrac{3.81 \ g}{74.5513 \ g/mol} \approx 0.051106 \ moles[/tex]

1 mole of a substance, contains Avogadro's number (6.022 × 10²³) of  formula units

Therefore;

0.051106 moles of KCl contains 0.051106 × 6.022 × 10²³  ≈ 3.077588 × 10²² formula units

From which we have, the number of formula units in 3.81 g of potassium chloride (KCl) ≈ 3.08 × 10²² formula units.

The number of formula units in 3.81 g of potassium chloride (KCl) is approximately 3.08 × 10²²

Given:

Mass of KCl= 3.81 g

To find:

Formula units of KCl=?

Molar Mass of KCl = 74.55 g/mol

So, substituting the values in order to calculate number of moles

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}} \\\\\text{Number of moles}=\frac{3.81}{74.55} \\\\\text{Number of moles}=0.051 \text{ moles}[/tex]

1 mole of a substance = Avogadro's number (6.022 × 10²³) of  formula units

Thus, 0.051 moles of KCl will contain

[tex]0.051106 * 6.022 * 10^{23} =3.077588 * 10^{22} \text{ formula units}[/tex]

→The number of formula units in 3.81 g of potassium chloride (KCl)

= 3.08 × 10²² formula units.

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Answer:

Mercury, Venus, Earth and Mars.

Explanation: