Which is the electron configuration for boron?
A.1s22s3
B.1s22s23s
C.1s'2s²2p?
D.1s22s²2p?

Answer:

Explanation:

d =

m

V

m = d×V

V =

m

d

DENSITY

Density is defined as mass per unit volume.

d =

m

V

Example:

A brick of salt measuring 10.0 cm x 10.0 cm x 2.00 cm has a mass of 433 g. What is its density?

Step 1: Calculate the volume

V = lwh = 10.0 cm × 10.0 cm × 2.00 cm = 200 cm³

Step 2: Calculate the density

d =

m

V

=

433

g

200

c

m

³

= 2.16 g/cm³

MASS

d =

m

V

We can rearrange this to get the expression for the mass.

m = d×V

Example:

If 500 mL of a liquid has a density of 1.11 g/mL, what is its mass?

m = d×V = 500 mL ×

1.11

g

1

m

L

= 555 g

VOLUME

d =

m

V

We can rearrange this to get the expression for the volume.

V =

m

d

Example:

What is the volume of a bar of gold that has a mass of 14.83 kg. The density of gold is 19.32 g/cm³.

Step 1: Convert kilograms to grams.

14.83 kg ×

1000

g

1

k

g

= 14 830 g

Step 2: Calculate the volume.

V =

m

d

= 14 830 g ×

1

c

m

³

19.32

g

= 767.6 cm³

The mass of rock is 10 g.

We have sample of rock.

We have to determine its mass.

The density and mass of body are related as follows -

D = M / V

where -

V -  volume of the body.

M - mass of the body.

D - density of the body.

According to the question →

Using the formula discussed above -

D = M / V

M = D x V

M = 2.5 x 4 = 10 g

Hence, the mass of rock is 10 g

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Answer : The number of grams of gold Bob take from the aliens will be 0.5.

Explanation :

As we are given that:

1 zygot = 3 trigots

3 trigots = 2 bigots

4 bigots = 1 gram gold

Now we have to determine the number of grams of gold Bob take from the aliens.

The number of grams of gold Bob take from the aliens will be equal to:

[tex]\frac{1\text{ zygot}}{1}\times \frac{3\text{ trigots }}{1\text{ zygot}}\times \frac{2\text{ bigots }}{3\text{ trigots }}\times \frac{2\text{ gram gold}}{4\text{ bigots }}[/tex]

= [tex]\frac{6}{12}[/tex] gram gold

= [tex]\frac{1}{2}[/tex] gram gold

=  0.5 gram gold

Hence, the number of grams of gold Bob take from the aliens will be 0.5.

Answer:

Ans : 22.86 gm of Aluminium

Solution,

                        3FeO + 2Al ---> 3 Fe + [tex]Al_{2}O_{3}[/tex]

Given                   3          2                    

Find                    1.27       x

By the given gms of FeO find its mole and put the moles in the find,

                                       [tex]n = \frac{given mass}{molecular mass}[/tex]

                  Given mass of FeO is 91.8

                   Molecular mass of FeO is 71.8

                                         n = [tex]\frac{91.8}{71.8}[/tex]  

                                         n = 1.27 moles of FeO  

Now solve for x,

                            [tex]x = \frac{2 x 1.27}{71.8}[/tex]

                             x = 0.85 moles

These are just moles of Aluminium that we need to react with FeO, so to find Grams of Aluminium we need,

                                Mass = moles x molecular mass

                                Mass = 0.85 x 27(atomic mass of Al)

                                Mass = 22.86 grams of aluminium is what we need

Answer:

Explanation:

The acceleration of an object given it's mass and the force acting on it can be found by using the formula

[tex]a = \frac{f}{m} \\ [/tex]

where

a is the acceleration

f is the force

m is the mass

From the question

f = 20 N

m = 5 kg

We have

[tex]a = \frac{20}{5} \\ [/tex]

We have the final answer as

Hope this helps you

Answer:

alkali metals

Explanation:

alkali metals only have one valence electron, meaning they are extremely reactive. they are considered the most reactive on the periodic table.

Answer: Lithium and Ethanol

Explanation: As lithium and ethanol both have a density of under

1.000g/ml, they can be supported by the water. Blood and Magnesium are denser than the water and will therefore sink as the water can not support it them.

the answer is: 9.80665

Answer:

The metal is Copper

Explanation:

Matter is composed of atoms, which is the smallest indivisible particle of an element. The atom of an element consists of three subatomic particles namely: proton, electron and neutron etc.

The proton, which is the positively charged particle, is equal to the electron, which is the negatively charged particle. The proton number of the atom is the ATOMIC NUMBER of an element.

In the periodic table, the element with atomic number 29, which also means proton number 29 is Copper (Cu).

Answer:

Bromin-79

Explanation:

The isotope bromine-79 will contain 35 protons, 35 electrons and 44 neutrons.

Answer:

Explanation:

2Ca    +    O₂   =    2CaO

80 g     32 g         112 g

given amount of Ca = 7.75 g

it will require oxygen =  32 x 7.75 / 80 = 3.1 g

but available oxygen = 2.44 so oxygen is the limiting reagent .

32g oxygen reacts with calcium to give 112 g of calcium oxide

2.44 gram of oxygen reacts with calcium to give 112 x 2.44 / 32 of CaO .

= 8.54 gram .

Theoretical yield of CaO = 8.54 gram.

Answer:

Explanation:

The density of a substance can be found by using the formula

[tex]density = \frac{mass}{volume} \\ [/tex]

From the question we have

[tex]density = \frac{52.2}{60} \\ [/tex]

We have the final answer as

Hope this helps you

Answer:

b?

Explanation:

The answer is C: Radiant energy from the sun travels through the glass, is absorbed by the black pot, and reflected by the aluminum foil.

Answer:

3 elements

Explanation:

The elements are:

- Chromium

- Hydrogen

- Oxygen

Answer:

m = 455,6 g

Explanation:

The mass can be determined by calculating the amount of substance times the molar mass:

m = n * M

To do this, you first have to calculate the molar mass of sodium oxalate. It is made up of the molar masses of the individual atoms. The molecular formula of sodium oxalate is:

[tex]Na_{2}C_{2}O_{4}[/tex]

M(Na) = 23 g/mol; M(C) = 12 g/mol; M(O) = 16 g/mol

M(Na2C2O4) = 2 * M(Na) + 2 * M(C) + 4 * M(O)

M(Na2C2O4) = 2 * 23 g/mol + 2 * 12 g/mol + 4 * 16 g/mol

M(Na2C2O4) = 134 g/mol

m = n * M

m = 3,4 mol * 134 g/mol

m = 455,6 g

Answer:sedimentary

Explanation:

Answer:Within the flower, sperm cells are produced by pollen at the tips of stamens, while egg cells develop in ovules, tiny structures embedded in the ovary at the base of the pistil.

I didn't realize the person up top had the same answer give them the brainliest! :)

Answer:

Mass of hydrogen produced is 0.07g.

Explanation:

Given data:

Mass of magnesium = 7.73 g

Mass of water = 1.31 g

Reaction yield = 88.2%

Mass of hydrogen produced = ?

Solution:

Chemical equation:

Mg + 2H₂O     →   Mg(OH)₂ + H₂

Number of moles of water:

Number of moles = mass/ molar mass

Number of moles = 1.31 g / 18 g/mol

Number of moles = 0.07 mol

Number of moles of magnesium:

Number of moles = mass/ molar mass

Number of moles = 7.73 g / 18 g/mol

Number of moles = 0.43 mol

Now we will compare the moles of water and magnesium with hydrogen.

                    Mg            :           H₂

                     1               :            1

                    0.43          :          0.43

                    H₂O          :             H₂

                      2             :              1

                   0.07           :            1/2×0.07 = 0.035

Mass of hydrogen:

Mass = number of moles × molar mass

Mass = 0.035 mol × 2 g/mol

Mass = 0.07  g

Answer: 0.064 grams is the answer

Explanation:

at the end you must multiply 88.2/100*0.073=0.064

Answer: C

Explanation: I looked it up lol

Answer:

An unknown being weighed is hygroscopic. - operative error

One component of a mixture being analyzed quantitatively by gas chromatography reacts with the column packing. - methodic error

The tip of the pipet used in the analysis is broken. - instrumental error

In measuring the same peak heights of a chromatogram, two technicians each report different heights - operative error

Explanation:

In chemical analysis, operative errors are that largely introduced into the measurement because of variation of personal judgements of analysts. It is also a personal error that emanates solely due to the analyst.

A methodic error arises as a result of adopting defective experimental methods. For example, a column packing that reacts with a component of the mixture is used in the gas chromatography.

Instrument error refers to the error of a measuring instrument, for instance, the use of a pipette with a broken tip.

Answer:

1. c

2. d

3. c

4. d

5.

6. a

7. a

8.

Answer:

–215 °C

Explanation:

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

Mass of Ne = 10.5 g

Volume (V) = 2.50 L

Pressure (P) = 1 atm

Temperature (T) =?

Next, we shall determine the number of mole present in 10.5 gof Neon, Ne. This can be obtained as follow:

Mass of Ne = 10.5 g

Molar mass of Ne = 20 g/mol

Mole of Ne =.?

Mole = mass /Molar mass

Mole of Ne = 10.5 / 20

Mole of Ne = 0.525 mole

Next, we shall determine the temperature of the sample of Neon, Ne. This can be obtained as follow:

Volume (V) = 2.50 L

Pressure (P) = 1 atm

Number of mole (n) = 0.525 mole

Gas constant (R) = 0.0821 atm.L/Kmol

Temperature (T) =?

PV = nRT

1 × 2.5 = 0.525 × 0.0821 × T

2.5 = 0.525 × 0.0821 × T

Divide both side by 0.525 × 0.0821

T = 2.5 / (0.525 × 0.0821)

T = 58 K

Finally, we shall convert 58 K to degree celsius (°C). This can be obtained as follow:

T(°C) = T(K) – 273

T(K) = 58 K

T(°C) = 58 – 273

T(°C) = –215 °C

Thus, the temperature of the sample of Neon gas is –215 °C.

Answer:

The answers are A. and D.

According to the concept of solubility and properties of ionic compounds, magnesium sulfate and sodium nitrate dissolve in water.

Solubility is defined as the ability of a substance which is basically solute to form a solution with another substance. There is an extent to which a substance is soluble in a particular solvent. This is generally measured as the concentration of a solute present in a saturated solution.

The solubility mainly depends on the composition of solute and solvent ,its pH and presence of other dissolved substance. It is also dependent on temperature and pressure which is maintained.Concept of solubility is not valid for chemical reactions which are irreversible. The dependency of solubility on various factors is due to interactions between the particles, molecule or ions.

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Answer:

The frequencies of light that an atom can emit are dependent on states the electrons can be in. When excited, an electron moves to a higher energy level or orbital. When the electron falls back to its ground level the light is emitted.

Answer:

A Light is produced when an electron moves from a higher to a lower energy level.

Explanation:

Answer:

Difference between Contact and Non-Contact Forces

There is no field linked with the contact force. There is always a field linked with non-contact force. The frictional force is an example of a contact force. Gravitational force is an example of a non-contact force.

Explanation:

And it is physics not chem.

Hope this helps u

Crown me as brainliest:)

Answer:

the marble would hit the floor first because the feather would be effected by air resistance

Answer:

Explanation:

The force acting on an object given it's mass and acceleration can be found by using the formula

From the question we have

force = 0.5 × 3

We have the final answer as

Hope this helps you

Answer:

8.7g/mL

Explanation:

I used the density formula to solve. d=m/v= 20g/2.3mL

Answer:

8.7 g/ml

Explanation:

the formula for density is D = M/V