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3 years ago

NEED HELP ASAP ITS DUE TODAY THESE QUESTIONS

Chemistry

1 answer:

beks73 [17]3 years ago

6 0

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 %

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mr_godi [17]

Answer:

The two types of collisions are :

Type a)

Elastic collision

Type b)

Inelastic collision

Explanation:

Collision : It is the event when two bodies collide with each other for small period of time.

During collision , the bodies exert force to each other.

Example :

When boxer hits with punches .

When bat hits the ball in cricket match.

So, collision is short duration interaction of two objects. When the objects collides , there is change in their velocity.

All collision follow law of conservation of momentum . Their type is decided by , whether they follow conservation of energy also.

Compare and contrast the two types

a) Elastic collision : Those collision in which no loss or gain of kinetic energy will occur. They follow conservation of kinetic energy. Example : ideal gaseous molecule

b) Inelastic collision : Those collision in which Change in kinetic energy will occur. They do not follow conservation of kinetic energy.Almost all conservation are inelastic.

Here Kinetic energy get converted into other form of energy.

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3 years ago

Fireworks, KNO3 Give only the names of the elements alphabetically, separating them with commas.

Alborosie

Answer : The question is to write the elements alphabetically and seperating them with commas.

So in this case for your question of Fireworks , K $NO_{3}$ ,

The answer will be K, N, O.

You have to just differentiate the elements and write them according to the alphabetical order.

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3 years ago

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dem82 [27]

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4. Rock Melting.
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3 years ago

Predict whether the equilibria I) CH4(g) + H2O(g) ⇀↽ CO(g) + 3 H2(g), ∆H◦ = +206 kJ II) 2 SO2(g) + O2 ⇀↽ 2 SO3(g), ∆H◦ = −198 kJ

Dima020 [189]

Answer:

(1) I shifts toward product and II shifts toward reactant.

Explanation:

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Increasing the temperature of an exothermic reaction (∆H is negative) shifts the equilibrium position to the left thus favoring the backward reaction.

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3 years ago

3. Two different compounds are formed by the elements carbon and oxygen. The first compound contains 42.9% by mass carbon and 57

mars1129 [50]

Answer:

The law of multiple proportions is the third postulate of Dalton's atomic theory. It states that the masses of one element which combine with a fixed mass of the second element are in a ratio of whole numbers.

Therefore, the masses of oxygen in the two compounds that combine with a fixed mass of carbon should be in a whole number ratio. In 100 grams of the first compound (100 is chosen to make calculations easier), there are 57.1 grams oxygen and 42.9 grams carbon. The mass of oxygen (O) per gram of carbon (C) is:

57.1 g O / 42.9 g C = 1.33 g O per g C

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72.7 g O / 27.3 g C = 2.66 g O per g C

Dividing the mass O per g C of the second (larger value) compound:

2.66 / 1.33 = 2

This means that the masses of oxygen that combine with carbon are in a 2:1 ratio. The whole-number ratio is consistent with the law of multiple proportions.

Explanation:

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