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2 years ago

I need help with question 2 I will brainliest you if I’m able to

Chemistry

2 answers:

erik [133]2 years ago

4 0

Answer:

Blank 1: Microscope

Blank 2: Cells

vfiekz [6]2 years ago

3 0

Answer: (answers are in bold)

Because of the invention of the microscope, we know that all organisms are made of small living creatures called cells.

Explanation:

Well the statement explains itself; I'll explain the invention of the microscope.

No one really knows who invented the simple microscope, but the compound microscope was invented c. 1590 by Dutch lens-maker Zacharias Janssen. He used it to magnify object to about 10x their original size. Anton von Leeuwenhoek made even better ones; those had up to 275x magnification.

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How to prepare 250.00 ml of approximately 1.0 m hcl solution from the 2.5 m hcl solutio?

kirill115 [55]

To solve this we use the equation,

M1V1 = M2V2

where M1 is the concentration of the stock solution, V1 is the volume of the stock solution, M2 is the concentration of the new solution and V2 is its volume.

2.5 M x V1 = 1.0 M x .250 L

<span>V1 = 0.10 L or 100 mL of the 2.5 M HCl solution is needed

Hope this helps.</span>

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3 years ago

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If you had 100 ml of juice, how many milliliter would de fruit juice?

Julli [10]

Since the measurement is not changing, the answer is 100 mL. Hope this helps.

8 0

3 years ago

An atom of the element iron has an atomic number of 26 and an atomic mass number of 56. if it is neutral, how many protons, neut

allsm [11]

<span> 26 protons, 30 neutrons, 26 electrons</span>

6 0

3 years ago

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When the concentration of A in the reaction A ..... B was changed from 1.20 M to 0.60 M, the half-life increased from 2.0 min to

Reika [66]

Answer:

$0.4167\ \text{M}^{-1}\text{min}^{-1}$

Explanation:

Half-life

${t_{1/2}}A=2\ \text{min}$

${t_{1/2}}B=4\ \text{min}$

Concentration

${[A]_0}_A=1.2\ \text{M}$

${[A]_0}_B=0.6\ \text{M}$

We have the relation

$t_{1/2}\propto \dfrac{1}{[A]_0^{n-1}}$

$\dfrac{{t_{1/2}}_A}{{t_{1/2}}_B}=\left(\dfrac{{[A]_0}_B}{{[A]_0}_A}\right)^{n-1}\\\Rightarrow \dfrac{2}{4}=\left(\dfrac{0.6}{1.2}\right)^{n-1}\\\Rightarrow \dfrac{1}{2}=\left(\dfrac{1}{2}\right)^{n-1}$

Comparing the exponents we get

$1=n-1\\\Rightarrow n=2$

The order of the reaction is 2.

$t_{1/2}=\dfrac{1}{k[A]_0^{n-1}}\\\Rightarrow k=\dfrac{1}{t_{1/2}[A]_0^{n-1}}\\\Rightarrow k=\dfrac{1}{2\times 1.2^{2-1}}\\\Rightarrow k=0.4167\ \text{M}^{-1}\text{min}^{-1}$

The rate constant is $0.4167\ \text{M}^{-1}\text{min}^{-1}$

3 0

2 years ago

In 1939, the use of DDT (a powerful synthetic chemical) as an insecticide was discovered. The United States adopted its widespre

Natasha_Volkova [10]

Main advantages of DDT are the insecticide property and the knoledge about its chemical synthesis.

Explanation:

At that time in 1939 it was discovered that DDT have insecticide properties. It is a useful property because it allows inhibition of insects populations in large areas. Killing insects will reduce the diseases transmitted by them as typhus and malaria. More over you prevent the destruction of the agricultural crops by the harmful insects.

However the synthesis of the molecule was known way back in 1874. From that time it was plenty of time in which chemistry knowledge evolved so the synthesis at kilograms scale was implemented. High quantities of DDT molecule become available for the market so that in 1945 was available as agricultural insecticide.

It was discovered that DDT have bad effects for human health and also over time some insects developed resistance and their were not affected anymore by the molecule.

You may find the chemical structure of DDT in the attached figure.

Lean more:

about DDT

brainly.com/question/1417051

#learnwithBrainly

8 0

3 years ago