What is the electron configuration of an element with atomic number 20? A. 1s2 2s2 2p6 3s2 3p5 B. 1s2 2s2 2p6 3s2 3p6 C. 1s2 2s2 2p6 3s2 D. 1s2 2s2 2p6 3s2 3p6 4s2 E. 1s2 2s2 2p6

Answer:- 0.34 M

Solution:- 127 grams of calcium nitrate are dissolved in water to make the volume of the solution 2300 mL. It asks to calculate the molarity of the solution.

Molarity is moles of solute per liter of solution. let's convert the given grams of the solute to moles on dividing it's grams by molar mass and convert the mL to L . Then the moles are divided by the liters to get the molarity. M is the symbol for molarity.

Calcium nitrate contains one Ca, two N and six O.  The molar mass is calculated as:

Molar mass = 40.078 + 2(14.007) + 6(15.999)

= 40.078 + 28.014 + 95.994

= 164.086 grams per mol

Conversion of grams to moles:

[tex]127g(\frac{1mol}{164.086g})[/tex]

= 0.774 mol

Conversion of mL to L:

[tex]2300mL(\frac{1L}{1000mL})[/tex]

= 2.3 L

Now, divide the moles by liters to get the molarity:

Molarity = [tex]\frac{0.774mol}{2.3L}[/tex]  = 0.34 M

So, the molarity of calcium nitrate solution is 0.34 M.

Answer 0.34 m

Explanation:

i got i right

Answer:- Ca = +2, S = +6 and O = -2

Solution:- There are certain rules for oxidation numbers. As per the rule, oxidation number of alkaline earth metals in their compounds is +2.

Oxidation number of oxygen in it's compounds is -2(except peroxides) and the sum of oxidation numbers of all the elements of a neutral compound is zero.

Since, Ca is +2 and O is -2, the oxidation number of S could easily be calculated for the given compound as:

Let's say the oxidation number of S in [tex]CaSO_4[/tex] is [tex]x[/tex] . Let's make the algebraic equation and solve it.

[tex]2+x+4(-2)=0[/tex]

[tex]2+x-8=0[/tex]

[tex]x-6=0[/tex]

[tex]x=+6[/tex]

Hence. the oxidation number of Ca is +2, O is -2 and S is +6.

Answer:

Ca = +2, S = +6 and O = -2

Explanation:

EDMENTUM

Annual precipitation is the amount of rain that falls in a specific geographic area over one year. It affects ecosystems, agriculture, and human activities. Extraordinary rainfall in the past has led to poor harvests and population loss.

Annual precipitation refers to the amount of rain that falls in a specific geographic area over the course of one year. It is a key component of the climate of a region and plays a significant role in shaping ecosystems, agriculture, and human activities.

For example, in 1314, Europe and Asia experienced a period of abnormally cold and wet winters due to extraordinary rainfall. This led to poor harvests and population loss. Similarly, in North America, established agricultural systems faltered under hotter summers and colder winters, resulting in severe population loss in the southwestern region.

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Hello there!

First you had to multiply by the density by the volume since D=M/V. Please make sure when your units has the same thing and it should be cancel it out.

2.3g/mL*30 mL= 69L is the right answer.

Hope this helps!

Thank you for posting your question at hereon Brainly.

-Charlie

The mass of a liquid is determined by multiplying its volume by its density. Given the density of 2.3 g/mL and the volume of 30 mL, the mass of the liquid is 69 g.

The mass of a liquid can be ascertained by multiplying its volume by its density. This is due to the relationship: mass = volume x density. Given the density of the liquid is 2.3 g/mL and the volume is 30 mL, we calculate the mass as: mass = volume x density = 30 mL x 2.3 g/mL = 69 g. Hence, the mass of the liquid is 69 g.

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The answer is C, The sports drink

The correct answer is Step 2. Step 2 is incorrect in Ben's calculation.

Step 2: Divide the result obtained in step 1 by 60.

Ben should have multiplied by the result obtained in step 1 by 60. That give the km covered per minute. This is because 60 sec is equal to 1 min.

In 1 sec the distance covered is (4.9 x 1.6) km

So in 60 sec or in 1 min the distance covered will be (4.9 x 1.6 x 60) km

A stretched rubber band has potential energy.

Potential energy is the energy of position.

You put work energy into the band when you stretched it.

Now, the band has the potential to do work when you let go and allow it to return to its unstretched state.

All are true except the statement that ions are formed by changing the number protons in an atom’s nucleus.

A neutral atom contains the same number of protons (positive charge) and electrons (negative charge).

If there are more electrons than protons, the atom becomes a negative ion.

If there are fewer electrons than protons, the atom becomes a positive ion.

The protons are in the nucleus, where we can’t easily get at them. The electrons are outside the nucleus, so other chemicals can easily get at them and either remove them or add to their number.

Metals have only a few valence electrons, so it is fairly easy to remove them and form positive ions.

Hey there!

Mass = 640 g

Density = 0.8 g/mL

Volume = ?

Therefore:

D = m / V

0.8 = 640 / V

V = 640 / 0.8

V = 800 mL

hope that helps!

Answer:

The answer is: 0.8 Liters

Explanation:

In order to find the volume of the oil, we have to divide the weight of the oil over the density, so we are going to know the volume in mL:

(640 g) / (0.8 g/ml) = 800 mL

Now, if we want the answer in liters, and we know 1 L (liter) is 1000 mL (mililiters), just divide 800 mL over 1000.

By applying Charles's Law (V1/T1 = V2/T2), we can calculate that the volume of a sample of gas, which originally occupied 32.0 cm³ at 189K, would expand to approximately 40.9 cm³ at 242K.

The volume of a sample of gas changing with temperature is explained by Charles's Law, which states that, at a constant pressure, the volume of a gas is directly proportional to its absolute temperature. In this case, you are given an initial volume (V1) of 32.0 cm³ at an initial temperature (T1) of 189K, and you need to find the final volume (V2) at a final temperature (T2) of 242K.

Using Charles's Law (V1/T1 = V2/T2), you can plug in the given values and solve for V2:

V2 = (V1 * T2) / T1

= (32.0 cm³ * 242K) / 189K

= approximately 40.9 cm³

So, the sample of gas would occupy a volume of approximately 40.9 cm³ at 242K, assuming constant pressure.

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The stored energy of an object is kinetic energy

Answer: potential

Explanation: because kinetic is when a object is in motion

if this is is a True or False question I think it would be (False). Because the continental crust is lighter than the oceanic crust, and the continental crust cannot subduct.

Answer:

False.

Explanation:

Ocean lithosphere is about 60km thick and very dense, whereas continental lithosphere is about 120km and less dense. That is why when they collide, ocean plates subduct under continental ones.

Percent error is the difference between the measured and known value, divided by the known value, multiplied by 100%.

So first, we take our measured value, .299 cm, minus our known value, .225 cm.

.299 cm - .225 cm=.004 cm

Next, we divide that by our known value

[tex]\frac{.004}{.225}=.0177777778[/tex]

Finally, multiply your answer by 100

.0177777778 x 100= 1.77777778 %

Round to three significant figures, and you're done.

=1.78 % error

Final answer:

The percentage error in the length measurement of 0.229 cm, with the correct value being 0.225 cm, is calculated to be 1.78%.

Explanation:

To calculate the percentage error of a length measurement, you can use the formula:

Percentage Error = (|Measured Value - True Value| / True Value) × 100%

Using the given values, where the measured value is 0.229 cm and the true value is 0.225 cm, the percentage error is calculated as follows:

Percentage Error = (|0.229 cm - 0.225 cm| / 0.225 cm) × 100%
                = (0.004 cm / 0.225 cm) × 100%
                = 0.0178... × 100%
                = 1.78%

Therefore, the percentage error in the length measurement is 1.78%.

The pH scale for acids and bases ranges from 0-to 14. Hence, option B is correct.

The potential of hydrogen is a measure of the acidity or alkalinity of a solution equal to the common logarithm of the reciprocal of the concentration of hydrogen ions in moles per cubic decimetre of solution.

pH is a measure of how acidic/basic water is.

The range goes from 0 - to 14, with 7 being neutral.

pHs of less than 7 indicate acidity, whereas a pH of greater than 7 indicates a base.

Hence, option B is correct.

Learn more about pH here:

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Answer : The energy of photon = [tex]21.369\times 10^{-19}J[/tex]

Solution : Given,

Final energy level = 1

Initial energy level = 7

Formula used :

[tex]\frac{1}{\lambda}=R[ \frac{1}{n^2_{final}}- \frac{1}{n^2_{initial}}][/tex]    ..........(1)

where,

[tex]\lambda[/tex] = wavelength

R = Rydberg's constant = 1.0974 [tex]\times 10^7m^{-1}[/tex]

[tex]n_{final}[/tex] = final energy level

[tex]n_{initial}[/tex] = initial energy level

Now put all the given values in above formula (1), we get the value of wavelength.

[tex]\frac{1}{\lambda}=1.0974\times 10^7m^{-1} [\frac{1}{1^2}- \frac{1}{7^2}][/tex] =  [tex]1.0750\times 10^7m^{-1}[/tex]

[tex]\lambda=0.9302\times 10^{-7}m[/tex]

Now we have to calculate the energy of photon by using formula,

[tex]E=\frac{h\times c}{\lambda}[/tex]

where,

E = energy

h = planck's constant = [tex]6.626\times 10^{-7}Js[/tex]

c = speed of light = [tex]3\times 10^8m/s[/tex]

[tex]\lambda[/tex] = wavelength

put all the values in this formula, we get the energy of photon.

[tex]E=\frac{6.626\times 10^{-7}Js\times 3\times 10^8m/s}{0.9302\times 10^{-7}m}[/tex] = [tex]21.369\times 10^{-19}J[/tex]

The energy of the photon emitted when an electron in a hydrogen atom transitions from n=7 to n=1 is -13.1 eV or 2.1 x 10^-18 J. This means the atom is emitting energy.

To calculate the energy of a photon emitted when an electron in a hydrogen atom undergoes a transition from n=7 to n=1, we can use the following equation for the energy differences in a hydrogen atom: ΔE = E_final - E_initial = -13.6 eV (1/n_final² - 1/n_initial²). In this case, the final state (n_final) is 1 and the initial state (n_initial) is 7.

Substitute these values into the equation to get: ΔE = -13.6 eV (1/1² - 1/7²) = -13.1 eV. This indicates that the energy of the photon emitted is 13.1 electron volts (eV). The negative sign indicates energy emission.

The numerical value can alternatively be converted to Joules (the SI unit for energy) by multiplying with the charge of an electron (1.6 x 10^-19 C): ΔE = 13.1 eV * 1.6 x 10^-19 C/eV = 2.1 x 10^-18 J.

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The answer to your question is,

B. Streak

-Mabel <3

A. C. and D. do not have anything to do with colours.

The answer to your question is B. Streak is a line that differs from its surroundings by its colour.

Hope it helped,

BioTeacher101

The total amount that Staci had in hand is $200.00.

The ticket at that time costs $87.96.

One Tshirt costs, $30.00.

Now that she has paid ticket, she will deduct the ticket from the cash she has in hand, so as to know the amount she is remaining with.

Tha is, $200-$87.96 = $112.04.

∴ In hand Staci has $112.04 extra cash whereby she can purchase more t shirts.

To get the number of tshirt she can buy, she will divide the amount she has in hand by the amount per piece of t shirt.

For example, $112.04 / $30 = $3.73.

∴ Staci can only purchase threet shirts only at a total cost of $90 for all the t shirts which is $30 × 3 = $90.

Staci has excess of 22.04 after deducting ticket and the other amount she has used to purchase the extra t shirts.

That is, $112.04 - $90 = $22.04.

She can buy Three shirts.

Total money of staci = $200.00

The ticket's cost     = $87.96

Price of one shirt     =  $30.00

Shirts bought by staci = ?

Solution:

Money left after ticket purchase = $200 - $87.96

                                                      =  $112.04

         No. of shirts she can buy   =  $112.04/$30 = 3.73

                                                      =  Three shirts she can buy.

Explanation:

When a charged object is brought near a neutral object and when both of them touch each other then the neutral object also acquires the same charge that is present on the charged object.

This process of charge transfer is known as conduction.

So, when a ruler that is negatively charged touches a metal rod then the metal rod also becomes negatively charged because of conduction process.

This is because negative charge moves from the rules towards the metal rod and hence, it spreads over to the metal rod.

When you rub a ruler against a metal rod, something called charging by friction happens and the ruler can transfer charge to the rod.

When you rub a ruler against a metal rod, something called charging by friction happens and the ruler can transfer charge to the rod. Here is a simple explanation of how charge is transferred, explained step-by-step:

Starting Point: At first, the ruler and metal rod have the same amount of positive and negative charges, which makes them neutral.

Contact: The ruler touches the metal rod. When the ruler touches the rod, some of the electrons from the atoms in the ruler can move to the atoms in the rod.

To create friction, we rub the ruler against the metal rod while they touch each other. When you rub the ruler against the rod, they touch each other more strongly and exchange electrons.

When the ruler rubs against the rod, some of the electrons from the ruler's surface may move onto the rod's surface. This movement of electrons creates an uneven charge between the two objects.

Charge separation occurs when electrons are transferred. In this case, the ruler has gained extra electrons and becomes negatively charged, while the metal rod loses electrons and becomes positively charged.

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it would be liquid moves but never bounces off(evaporates)

Answer:

liquid

Explanation: lets eliminate answers

first,it can be gas cuz gases bounce off

it cant be solid cuz they dont move they just vibrate

it cant be plasma cuz plasma molecules bounce apart and when the molecules seed up they bounce apart.  

therefore it is  liquid cuz they move around and dont bounce off

i also got this right on my flvs science test

The answer depends on what substances you were testing, but here are some ideas.

If all of them were white as in the typical experiment, then color is not very useful.  If you were allowed to taste them, then a salty taste would be a helpful clue.  If the textures were different, some crystals, like salt or sugar and others powdery, like flour or cornstarch, those properties would be helpful.  If some dissolved in water,...

Both physical and chemical properties can be used to identify a mystery powder. Physical properties include characteristics like color, texture, mass, and volume, while chemical properties entail reactions with other substances or heat.

In order to identify a mystery powder, both physical and chemical properties can be highly useful. Physical properties, such as the powder's color, texture, mass, and volume can give us certain clues about the substance. For instance, certain substances may have a specific color or texture unique to them.

On the other hand, chemical properties are equally useful. These include reactions the powder has to various chemicals or heat, and its ability to burn or support burning. For example, if a powder reacts vigorously with an acid, it could be a base. If it burns with a certain color flame, it could be a specific type of metal.

Therefore, the choice between using physical or chemical properties often depends on the mystery powder in question. However, a combination of both types of properties can provide the most accurate identification.

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Metals in the Periodic Table are grouped together due to their similar properties, mainly driven by their outer electron configurations. This includes the representative, transition, and inner transition metals, each of which have unique electron filling patterns.

Metals are grouped together in the Periodic Table because of the similarity in their properties. This is a result of their similar outer electron configurations. The grouping of metals includes the representative metals, transition metals, and inner transition metals, which are classified based on the filling orbital.

Representative metals are elements in which the s and p orbitals are filling. These metals are found in groups 1, 2, 3, 12, 13, 14, and 15 of the Periodic Table. Examples of these metals include the alkali metals (group 1) and the alkaline earth metals (group 2). The elements in these groups share common properties, such as their reactivity with water and air.

Transition metals and inner transition metals are elements which have d and f orbitals filling, respectively. These metals exhibit high thermal and electrical conductivity among other physical and chemical properties.

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The tool that is used to measure object's mass is electronic balance. The correct option is D.

An electronic balance is a device used to accurately measure the weight of materials. Electronic balances are important laboratory instruments for precise measurement of chemicals used in various experiments.

A laboratory electronic balance provides a digital measurement result. Thermometer is the one that is used to measure temperature.

Digital scales are generally more accurate than mechanical ones. However, for the most accurate reading, any bathroom scale must be properly set up and used consistently.

A graduated cylinder is a piece of laboratory equipment used to measure the volume of liquids, chemicals, or solutions during the course of a day's work in the lab.

A meter stick is a measuring device that measures one meter (one hundred centimeters) and is used to measure things in meters and centimeters.

Thus, the correct option is D.

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Answer:  2 H₂  +  O₂    →    2 H₂O

Reasoning:

When balancing an equation, what you are trying to do is to ensure that the amount of each atom on the right side (reactant side), is equal to the amount of each atom on the left side (product side), because of the law of conservation of energy.

∴ the balanced equation is     2 H₂  +  O₂    →    2 H₂O

The volume of a gas that is required  yo react with 4.03 g mg  at STP  is 1856 ml

calculation/

     moles=mass/molar mass

moles of Mg is therefore=4.03 g/  24.3 g/mol=0.1658  moles

  the moles 02=0.1679 x1/20.0829 moles

                            0.0895 moles=? L

into Ml = 1.8570 x1000=1856  ml  approximately to 1860

The volume of oxygen gas required to react with 4.03 g of Mg at STP is approximately 1860 mL, calculated by first determining the moles of Mg, then the stoichiometric ratio with oxygen, and applying the gas volume at STP.

To find out what volume of oxygen gas is required to react with 4.03 g of Mg at STP, we first need to calculate the number of moles of magnesium. The molar mass of Mg is 24.305 g/mol. Therefore, the moles of Mg in 4.03 g can be calculated by the formula:

moles of Mg = mass of Mg / molar mass of Mg

moles of Mg = 4.03 g / 24.305 g/mol = 0.1658 moles Mg.

According to the balanced chemical equation 2Mg(s) + O₂(g) → 2MgO(s), 2 moles of Mg reacts with 1 mole of O₂, hence, 0.1658 moles of Mg will react with half that amount of O₂, which is 0.0829 moles of O₂.

At STP (Standard Temperature and Pressure), 1 mole of any gas occupies 22.4 liters or 22,400 milliliters. Therefore, the volume of O₂ gas required is:

volume of O₂ = moles of O₂ * volume occupied by 1 mole of gas at STP

volume of O₂ = 0.0829 moles * 22,400 mL/mol = 1856.96 mL, which can be rounded to 1860 mL (Choice A).

You have elements, compounds, and mixtures.

Salt water is a mixture.

Answer:- 240029 cans.

Solution:- As per the given information, 32537 cans were collected in September and 207492 cans were collected in October. It asks how many Cans were collected in October and September.

It is an addition problem so let's add the two given numbers of cans:

Total cans = 32537+207492 = 240029

So, 240029 cans were collected in October and September.

Liberty Elementary School collected a total of 240,029 cans in September and October, by adding 32,537 cans collected in September to 207,492 cans collected in October.

The question asks to find the sum of cans collected in September and October by Liberty Elementary School. In September, they collected 32,537 cans and in October they collected 207,492 cans.

To find the total number of cans collected over the two months, we add the number of cans collected in September to the number of cans collected in October:

32,537 (September) + 207,492 (October) = 240,029

Hence, the total number of cans collected in September and October is 240,029.

A hypothesis is a suggested solution for an unexplained occurrence that does not fit into current accepted scientific theory. The basic idea of a hypothesis is that there is no pre-determined outcome.

Answer:the answer is A

Explanation:

In the four-stroke engine cycle, the spark plug initiates the combustion reaction during the ignition stage, which is part of the power stroke. Correct timing of the spark is crucial for the engine's efficient operation.

The spark plug initiates the combustion reaction during the ignition stage of the four-stroke engine cycle. Specifically, ignition occurs in the third step of the cycle, known as the power stroke. This stage involves two main parts:

It is vital for the spark to occur at the correct time to ensure that the fuel burns efficiently and that the engine operates smoothly, avoiding issues such as knocking or pre-ignition.

Final answer:

The spark plug initiates the combustion reaction during the power stroke of the four-stroke engine cycle, which is when the majority of the engine's power is produced.

Explanation:

In the four-stroke internal combustion engine cycle, the spark plug initiates the combustion reaction during the power stroke. After the air-fuel mixture is compressed during the compression stroke, the spark plug ignites the mixture at the beginning of the power stroke. This ignition converts chemical potential energy into thermal energy, causing a significant increase in pressure that forces the piston down, thereby doing work on the crankshaft in an adiabatic process. The cycle consists of four main strokes: the intake stroke, the compression stroke, the power stroke, and the exhaust stroke. The power stroke is also when the engine delivers the majority of its power to the crankshaft, making it a critical part of the engine's operation.

Answer: HBr has the lowest rate of effusion at a given temperature.

Explanation: The effusion rate usually increases with increase in temperature because the kinetic energy of the gaseous molecules increases. But it was not true for gases having heavier mass. This was explained by Graham's Law.

Graham's Law states that the rate of effusion of a gas is inversely proportional to the square root of its molecular weight.

[tex](\text{Rate of effusion})_A\propto \frac{1}{\sqrt{\text{Mol. mass}_A}}[/tex]

We are given different gases with different Molecular masses. The gas having larger Molecular mass will have the lowest rate of effusion.

Mol. Mass of [tex]SO_3[/tex] = 80 g/mol

Mol. Mass of [tex]CH_4[/tex] = 16 g/mol

Mol. Mass of [tex]NH_3[/tex] = 17 g/mol

Mol. Mass of HBr = 81 g/mol

Mol. Mass of HCl = 36 g/mol

As, Mol. mass of HBr is the highest, so its rate of effusion will be the lowest.