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3 years ago

Indentify two advantages in daylight saving time

2 answers:

7 0

Hello Melindayosiff !

Two advantages in daylight saving time are...

- It saves electricity use (it decreases use of electricity)
- It provides and extra hour of daylight at night

I hope I was able to help you out ! :D

Savatey [412]3 years ago

5 0

More sleep and longer days or nights

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NEED HELP ASAP ITS DUE TODAY THESE QUESTIONS

beks73 [17]

Density can be defined as the mass of the substance in unit volume.

Density = mass / volume

Hence, g/mL and kg/L can be used as the units of density.

Those units are interchangeable because when converting one unit into other one nothing will happen to the value.

That is because when converting the g into kg, you have to multiply the value by 1 x 10⁻³. When converting mL into L, you should again multiply the volume by 1 x 10⁻³. Then those 1 x 10⁻³ will cancel off and the original value will remain as same.

Answer is 2.70 g/mL.

Explanation;

Mass of the block = 146 g

Volume of the block = length x width x height

= 6.0 cm x 3.0 cm x 3.0 cm

= 54 cm³ = 54 mL

Density = mass / volume

= 146 g / 54 mL

= 2.70 g/mL

Answer is 3.39 g/mL.

Explanation;

When immersing an object in a solution, the increased volume indicates the volume of that object.

Hence,

Volume of the object = increased volume of water level

= final volume - initial volume

= 27.8 mL - 21.2 mL

= 6.6 mL

Mass of the object = 22.4 g

Density = Mass / Volume

= 22.4 g / 6.6 mL

= 3.39 g/mL

Accepted value is the value that scientists and community accept as true. This is a theoretical value.

But the measured value is the value that you obtain from doing experiments. This is the actual value.

If your measured value is more close to the accepted value, then your measured value is more precise. But, if your measured value is far away from accepted value means that your value is not precise and there may have some errors.

Answers : Percent error is 9.11 %

The element which has 7.13 g/cm³ as density is Zinc (Zn).

Explanation;

Percent error can be calculated by using following formula.

% error = ( (measured value - accepted value) / accepted value ) x 100%

= ( (7.78 g/cm³ - 7.13 g/cm³) / 7.13 g/cm³ ) x 100%

= 9.11 %

6 0

3 years ago

Which of the following statements is true about the specific heat capacity of a substance?

Ludmilka [50]

Answer:

Option A

Explanation:

An intensive property is a bulk property, meaning that it is a local physical property of a system that does not depend on the system size or the amount of material in the system. Examples of intensive properties include temperature, T; refractive index, n; density, ρ; and hardness of an object,specific heat, η.

Physical properties can be observed or measured without changing the composition of matter. Physical properties are used to observe and describe matter. Physical properties include: appearance, texture, color, odor, melting point, boiling point, density, solubility, polarity, specific heat and many others.

6 0

3 years ago

Need help with this question.... Next to each Formula, write the number of atoms of each element found in one unit of the compou

Andrew [12]

Answer:

The number of atoms present in one unit of the following compounds is:

a). Potassium Iodide , KI = 2

b).Sodium Sulfide, $Na_{2}S$ = 3

c). Silicon Dioxide , $SiO_{2}$ = 3

d). Carbonic Acid , $H_{2}CO_{3}$ = 6

Explanation:

Atomicity : It is defined as the number of atoms that are present in a given molecule/compound.

Atom : The smallest unit of matter is called atom. For e.g O is atom of oxygen but $O_{2}$ is not an atom , it is molecule of oxygen .

$O_{2}$ molecule has 2 atoms of Oxygen

Similarly Na , K , Fe are atoms but $O_{2}$ , $CO_{2}$ , $N_{2}$ , $H_{2}$ are molecules

a).Potassium Iodide

KI = 1 atom of K + 1 atom of I

Total atoms = 2

b) Sodium Sulfide

$Na_{2}S$ = 2 atoms of Na + 1 atom of S

Total atoms = 3

c) Silicon Dioxide

$SiO_{2}$ = 1 atom of Si + 2 atoms of O

Total atoms = 3

d) Carbonic Acid

$H_{2}CO_{3}$ = 2 atom of H + 1 atom of C + 3 atom of O

= 2+1+3

Total atoms = 6

7 0

2 years ago

The pH at the equivalence point will be a. less than 7.00 b. equal to 7.00 Allohalineup of a sto quivalence point of a titration

True [87]

Answer: c. greater than 7.00

Explanation: The equivalence point of a titration is when all the base is consumed by the acid. When a strong base and a strong acid react, the medium is neutralized because is produced water and salt (which won't suffer hydrolysis). How water's pH is 7, in this type of titration the pH of the equivalence point will be at pH=7. But on titration of a weak acid with a strong base, the reaction of the equivalence point produces water and the conjugate base of the acid. Because the acid is weak, their conjugate base will be strong and will suffer hydrolysis, producing hydroxyl ions, elevating the pH of the water and making it greater than 7.

8 0

2 years ago

g Select the correct statements. I. Reduction is the loss of electrons, and oxidation is the gain of electrons II. Reduction is

Karolina [17]

Answer: The correct answer is Option D.

Explanation:

Reduction reaction is defined as the reaction in which a substance gains electrons. Here, the oxidation state of the substance decreases.

$X^{n+}+ne^-\rightarrow X$

Oxidizing agents are the agents that helps in the oxidation of other substance and itself gets reduced. These agents undergoes reduction reactions.

Oxidation reaction is defined as the reaction in which a substance looses its electrons. Here, oxidation state of the substance increases.

$X\rightarrow X^{n+}+ne^-$

Reducing agents are the agents that helps in the reduction of the other substance and itself gets oxidized. These agents undergoes reduction reactions.

Oxidation state is the number which is given to an atom when it looses or gains electron. It is written as a superscript. In a compound, the total charge is equal to the sum of the charges of all atoms in that compound. For Example: In $MnO_4^-$ , manganese has +7 oxidation number and oxygen has -2.

So, the charge on the compound = $[=7+(4\times (-2))]=-1$

Hence, the correct answer is Option D.

6 0

3 years ago