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3 years ago

Why was 1990 an important year regarding air quality?

Chemistry

2 answers:

DerKrebs [107]3 years ago

4 0

Answer:

100%

2 and 4

Explanation:

Valentin [98]3 years ago

3 0

Why was 1990 an important year regarding air quality? Check all that apply.

2.Cost-effective ways to reduce pollution were emphasized.

4.Modifications and improvements were made to the Clean Air Act.

i just took the test this is 100% correct

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3 years ago

A 6.1-kg solid sphere, made of metal whose density is 2600 kg/m3, is suspended by a cord. When the sphere is immersed in a liqui

deff fn [24]

Answer:

Density of the liquid = 1470.43 kg/m³

Explanation:

Given:

Mass of solid sphere(m) = 6.1 kg

Density of the metal = 2600 kg/m³

Thus volume of the liquid :

$Volume(V)=\frac{Mass(m)}{Density (\rho)}$

Volume of the sphere = 6.1 kg/2600 kg/m³ = 0.002346 m³

The volume of water displaced is equal to the volume of sphere (Archimedes' principle)

Volume displaced = 0.002346 m³

Buoyant force = $\rho\times gV$

Where

$\rho$ is the density of the fluid

g is the acceleration due to gravity

V is the volume displaced

The free body diagram of the sphere is shown in image.

According to image:

$mg=\rho\times gV+T$

Acceleration due to gravity = 9.81 ms⁻²

Tension force = 26 N

Applying in the equation to find the density of the liquid as:

$6.1\times 9.81=\rho\times 9.81\times 0.002346+26$

$33.841=\rho\times 9.81\times 0.002346$

$\rho=\frac{33.841}{9.81\times 0.002346}$

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3 years ago

A student placed a small chip of limestone into a hydrochloric acid solution, and carbon dioxide gas was released. The carbon di

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Physical and chemical changes are reversible and nonreversible changes. The release of carbon dioxide gas indicates a chemical change.

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A chemical change is a change in which a new substance is produced when the reactants react in the reaction mixture. The chemical produced cannot be reversed back to the reactants and hence, it is nonreversible.

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