Which of the following example(s) from everyday life are made possible by modern chemistry?

If you could help me out I would really appreciate it. Thank you!

Answer:

1) Yes the density does affect it's melting rate.

Explanation:

Simply because the more rock the more time. For instance an ice cube that is empty inside ( has less density ) will take less to melt. Verses an ice cube that is ice to its inner core ( has more density ) will take more time to melt in the same temperature as the first ice cube.

Answer:

1.7x10^8 Hz

Explanation:

Frequency could be explained as the number of occurrences of a repeating event at a time

Given:

wavelength = 1.8 meters

The frequency f of the waves can be calculated using f = c / λ

Where c (m/s) is the speed of the wave

λ (m) is the wavelength

Speed c= 3*10^8 m/s

Frequency f= 3*10^8 /1.8

Frequency= 1.7x10^8 Hz

Therefore,the frequency of waves from a radar detector is 1.7x10^8 Hz

Answer:

The amount of positive charge in a barium nucleus is approximately 8.972 × 10⁻¹⁸ coulomb

Explanation:

The amount of positive charge there is in a barium nucleus is found as follows;

The atomic number of an element is equal to the number of proton present in the atom

The atomic number of barium = 56 = The number of protons in an atom of barium

The positive charge of a single proton is known as an elementary charge, e, given by the formula, e = F/N[tex]_A[/tex]

Where;

F = Faraday's constant

N[tex]_A[/tex] = The Avogadro's number

Therefore, e = 1.602 176 634 × 10⁻¹⁹ C

Which gives the positive charge, Q, of the protons of a barium nucleus as follows;

Q = Number of protons × e

Q = 1.602176634 × 10⁻¹⁹ × 56 ≈ 8.972 × 10⁻¹⁸ Coulomb  per atom of barium.

The amount of positive charge in a barium nucleus ≈ 8.972 × 10⁻¹⁸ coulomb.

Answer:

+2

Explanation:

Answer: 0.5g/ml

Explanation:

The density of a substance is given by the following formular; Mass / Volume,

Where mass = 10g

           volume = 20ml

Density = 10g/ 20ml = 0.5g/ml

Answer:

1.375%

Explanation:

Percent Error = measured value - accepted value/ accepted value x 100

Measured Value: 15.78

Accepted Value: 16.00

Work:

[tex]\frac{15.78-16.00}{16.00}[/tex] * 100

[tex]\frac{-.22}{16}[/tex] * 100 = -1.375

You cannot have a negative percentage. Therefore the answer is 1.375%

Answer:

The answer is

Explanation:

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

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

From the question

mass = 837.21 g

volume = 37.00 mL

The density of the substance is

[tex]Density = \frac{837.21}{37} \\ = 22.62729[/tex]

We have the final answer as

Hope this helps you

Answer:

Explanation:

Q1) as we know that moles=given mass/molar mass

     mass of 5 moles of Mg is

mass =moles*molar mass

mass=5*24

mass=120 g

mass of 5 moles of CaCO3 is

mass= moles*molar mass

mass=5*100=500

Q2) number of atoms in 10 g Na

first we need number of moles of sodium

moles =mass/molar mass

moles=10/23=0.43

now we know that moles=number of atoms /avogadro number

for number of atom the formula become

number of atom=moles*avogadro number

number of atom=0.43*6.023*10^23=2.6*10^23

Q3)number of molecule in 10 g of NaCl

again we need number of moles of NaCl

moles=given mass/molar mass

moles=10/58.5=0.17

now number of molecules=moles*avogadro number

number of molecules=0.17*6.023*10^23=1.02*10^23

Q4) avogadro number is the number of particles(atoms,molecules,ions) present in one mole of a substance its value is 6.023*10^23

Q5)Number of atoms in 4g of oxygen

again we need number of moles of oxygen

moles=mass/molar mass

moles=4/16=0.25

now number of atoms=moles*avogadro number

number of atoms=0.25*6.023*10^23 =1.5*10^23

Answer:

because the volume

Explanation:

Answer:

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Answer The answer to this question is diesel.

Explanation:

Hi there, hope this helps!

Answer:

Always add acid to a large volume of water. The solution may then be diluted with additional water to make one liter. You'll get an incorrect concentration if you add 1 liter of water to the acid.

An acid is concentrated solution hence, it should be added to considerable quantity of water. The required volume can then be adjusted by adding more water.

Acids form aqueous solution and have the property of electric conductivity. Acids reacts with other molecules by forming a covalent bond.

Acids are corrosive in nature, sticky to touch, tastes sour and have strong smell.

Acids can be qualitatively detected through litmus test. They turn blue litmus paper red. Their pH is < 7 on pH scale.

Acids can be classified as:

Chemically, acids can react with other metals, carbonates and bases. Common examples of acids are vinegar (acetic acid), hydrochloric acid (HCl), sulfuric acid (H2SO4) etc.

Acids are found in food items such as citrus fruits. Acetic acid is widely used in certain food preparations and as food preservative. Acids are commercially used in dyes, paints and in soft drinks.

Thus, acids are important in many chemical reactions.

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Answer:

pretty sure its Scientific laws are statements about observed experimental facts, while theories are explanations of natural phenomena.

The statement that correctly explains the difference between a theory and a scientific law is as follows:

Thus, the correct option is B.

A Scientific theory may be defined as a well-explained fact that is significantly associated with the natural world that has been constructed through the utilization of the scientific method, and which brings together many facts and hypotheses.

A Scientific theory is based on observation. It is proven but still testable in nature in order to derive evidence. It generally does not possess mathematical statements and deductions. Theories are explained on nature as well as natural phenomena.

Scientific law is based on unalterable facts or those facts that remain constant. It is proven as well as contains evidence to support the claim. It definitely possesses mathematical statements and deductions.

Therefore, the correct option for this question is B.

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Answer:

false

in chemical reaction element doesnot change into another

Explanation:

Answer:

A

Explanation:

Answer:

Hypothesis. Hope this helped! :)

Answer:

The answer is B. Becomes moldy quickly.

Explanation:

This is the most logical answer out of all of them an I took the test.

60 J work does the student do on the bag.

The formula for work is as follows:-

[tex]W=F\times d[/tex]....(1)

Here, F is the force, and d is the distance moved in the direction of force.

Substitute 50 N for force and 1.2 m for distance in the equation (1) as follows:-

[tex]W=50\ N\times 1.2\ m\\\\=60\ Nm\\\\=60\ Joule[/tex]

Hence, the value of work is 60 J.

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Answer: A, Coniferous Forest.

Answer:

Tellurium

Explanation:

Technetium's position on the periodic table is 43 and Tellurium's is 52

A. kilogram is the SI unit used to measure mass of body.

B. litre is the SI unit used to measure volume of substance.

C. meter is the unit used to measure length of body.

D. Kelvin is the unit used to measure temperature of body.

Hence, (B) is the correct answer!

Cheers!

Explanation:

its its originality as an atom has to be pure

A different element is formed because the radioactive element has lost its originality as a pure atom when a radioactive element emits alpha radiation.

Some elements of unstable atomic nuclei undergo radioactive decay to form stable nuclei because of the presence of excess nuclear charge inside them are known as radioactive elements.

The stability of nuclei of an element can be estimated by neutron to proton ratio. The atomic number up to Z= 20 is stable nuclei and contains an equal number of protons and neutrons. As the atomic number starts to increase, the repulsion forces between protons increase.

Thus, the neutron-to-proton ratios of stable nuclei increase with increasing atomic numbers. If elements with the atomic number, Z > 83 and n/p > 1.5 and they will be most unstable and radioactive.

For example, Pu-240 emits an alpha particle and gets converted into U-236 which is completely different from the original nuclei.

²⁴⁰Pu₉₄  →   ⁴He₂  +   ²³⁶U₉₂

Therefore, the radioactive element lost its identity after disintegration.

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e temperature of a 0.750 L gas sample at 25°C and 2.00 atm is changed to 250°C.

Answer:

It represents the relationship between the distance travelled and time spent as constant or at a stop.

Explanation:

This is because as the line progresses, the time increases the distance should change as well my moving up or down, in a linear equation this relationship is constand but if the line is horizontal though, the distance is not changing despite time passing which means it has come to a stop.

Answer:

d= 4.8g/mL

m= 19.2 g

V=m/d

V= 4 mL

Answer:

The answer is Unreactive.

Explanation:

This is an unreactive atom because it has completely filled out stable electrons in the outer shell.

8 electrons in the outer shell means stable.

Answer:

The heat generated per gram of sample in calories is 0.87 g

Explanation:

Given that,

A calorimeter made from a can is used to measure the calories in a peanut.

During the experiment, the  measured calories were 35% of the true/accepted value given by references

Suppose, the mass of peanut is 0.4 g and find the

We need to calculate the heat generated per gram of sample in calories

Using formula of heat generated

[tex]q=\dfrac{q_{penut\ calorimeter}}{m_{peanut}}[/tex]

Put the value into the formula

[tex]q=\dfrac{0.35}{0.4}[/tex]

[tex]q=0.87\ g[/tex]

Hence, The heat generated per gram of sample in calories is 0.87 g

Answer:

Please find the description below

Explanation:

The density of a substance refers to its mass per unit of its volume i.e the amount of a substance contained in a given volume. The density is calculated using the formula:

Density = mass/volume

Using this formula, with the known value for mass and volume of the boat, the density of the boat can be calculated.

An object will FLOAT on a liquid substance if its density is lower than that of the liquid while it will SINK if it has a higher density than that of the liquid.

In this case, with a known density of water, which is 1g/cm^3 or 1000kg/m^3,

a boat placed on water will FLOAT if its density is <1g/cm^3 (less than) while it will SINK if its density is >1g/cm^3 (greater than).

Answer:

1. Cu = +2

2. O = – 2

3. C = +2

4. N = 0

Explanation:

Note:

A. The oxidation state of oxygen is always – 2 except in peroxides where it is – 1.

B. The oxidation state of Hydrogen is always +1 except in metallic hydrides where it is – 1.

Now let us solve the question given above.

1. CuO = 0 (ground state)

Cu + O = 0

O = – 2

Cu + (– 2) = 0

Cu – 2 = 0

Collect like terms

Cu = 0 + 2

Cu = +2

2. H2O = 0 (ground state)

2H + O = 0

H = +1

2(1) + O = 0

2 + O = 0

Collect like terms

O = 0 – 2

O = – 2

3. CO = 0 (ground state)

C + O = 0

O = – 2

C + (– 2) = 0

C – 2 = 0

Collect like terms

C = 0 + 2

C = +2

4. N2 = 0 (ground state)

2N = 0

Divide both side by 2

N = 0/2

N = 0