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3 years ago

I need help it is science agian

Chemistry

1 answer:

wolverine [178]3 years ago

8 0

Answer:

Kepler- created laws of planetary motion

Galileo- discovered moons of Jupiter; published in Italian

Copernicus- revived Aristarchus heliocentric model

Explanation:

I hope this helps you! :)

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What sentence about liquids is FALSE?'

iragen [17]

The answer would be c

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3 years ago

The independent variable has control and affects the

Stella [2.4K]

Answer:

The independent variable is the condition that you change in an experiment. It is the variable you control.

Explanation:

It is called independent because its value does not depend on and is not affected by the state of any other variable in the experiment. Sometimes you may hear this variable called the "controlled variable" because it is the one that is changed.

3 0

3 years ago

Read 2 more answers

What metalloid has commonly been used as an insecticide due to its effectiveness as a poison.

Taya2010 [7]

Answer:

Arsenic.

Explanation:

Hello there!

In this case, since insecticides are substances that act as poisons to get rid of insects in order to prevent their presence and/or reproduction in houses, companies, crops and others, a substance that has been widely used is the metalloid arsenic due to its direct affection of the insect's body (movement, performance, cellular functions).

In addition, high levels of arsenic in food could cause arsenic poisoning in humans as well, that is why such practice must be properly performed and by using the correct security protocol.

Best regards!

5 0

3 years ago

A chemistry teacher is able to grade chemistry labs at a rate of 5 labs for every 3 minutes. They need to grade 165 labs how man

PIT_PIT [208]

Answer:

1.65hr

Explanation:

Given parameters:

Number of labs = 5 labs

Time taken = 3 minutes

Unknown:

Time taken in hours to grade 165 labs = ?

Solution:

Let us find the rate of the teacher;

Rate = $\frac{number of labs}{time}$

Insert the parameters and solve;

Rate = $\frac{5}{3}$ = 1.67labs/min

Now;

Time to grade 165 labs = $\frac{number of labs}{rate}$

Time to grade 165 labs = $\frac{165}{1.67}$ = 98.8min

Since;

60min = 1hr

98.8min = $\frac{98.8}{60}$ = 1.65hr

3 0

3 years ago

Which of the following reactions could be an elementary reaction? 2 NO2(g) + F2(g) → 2NO2F(g) Rate = k[NO2][F2] H2(g) + Br2(g) →

podryga [215]

Answer: The correct answer is $NO(g)+O_2(g)\rightarrow NO_2(g)+O(g);Rate=k[NO][O_2]$

Explanation:

Molecularity of the reaction is defined as the number of atoms, ions or molecules that must colloid with one another simultaneously so as to result into a chemical reaction.

Order of the reaction is defined as the sum of the concentration of terms on which the rate of the reaction actually depends. It is the sum of the exponents of the molar concentration in the rate law expression.

Elementary reactions are defined as the reactions for which the order of the reaction is same as its molecularity and order with respect to each reactant is equal to its stoichiometric coefficient as represented in the balanced chemical reaction.

For the given reactions:

Equation 1: $2NO_2(g)+F_2(g)\rightarrow 2NO_2F(g);Rate=k[NO_2][F_2]$

Molecularity of the reaction = 2 + 1 = 3

Order of the reaction = 1 + 1 = 2

This is not considered as an elementary reaction.

Equation 2: $H_2(g)+Br_2(g)\rightarrow 2HBr(g);Rate=k[H_2][Br_2]^{1/2}$

Molecularity of the reaction = 1 + 1 = 2

Order of the reaction = $1+\frac{1}{2}=\frac{3}{2}$

This is not considered as an elementary reaction.

Equation 3: $NO(g)+O_2(g)\rightarrow NO_2(g)+O(g);Rate=k[NO][O_2]$

Molecularity of the reaction = 1 + 1 = 2

Order of the reaction = 1 + 1 = 2

This is considered as an elementary reaction.

Equation 4: $NO_2(g)+CO(g)\rightarrow NO(g)+CO_2(g);Rate=k[NO_2]^2$

Molecularity of the reaction = 1 + 1 = 2

Order of the reaction = 2 + 0 = 2

In this equation, the order with respect to each reactant is not equal to its stoichiometric coefficient which is represented in the balanced chemical reaction. Hence, this is not considered as an elementary reaction.

Hence, the correct answer is $NO(g)+O_2(g)\rightarrow NO_2(g)+O(g);Rate=k[NO][O_2]$

3 0

3 years ago