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4 years ago

What did scientists observe using the earliest microscopes

2 answers:

7 0

Using the earliest microscopes, scientists observed tiny organisms and cells. Antonie van Leeuwenhoek, the father of microbiology, was the first one who noted and described microorganisms. He named these microorganisms as "animalcules" which means tiny animals. These microorganisms are unicellular.

aleksandr82 [10.1K]4 years ago

4 0

Answer:

tiny ORGANISMS

Explanation:

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What is the [ H3O+] of a solution with pH = (8.50x10^0)? enter your answer in scientific notation and with three sig figs.

erastovalidia [21]

Answer:

[H₃O⁺] = 3.162 × 10⁻⁹ moles / liter

Explanation:

The pH is calculated with the formula:

pH = -lg[H₃O⁺]

From here the concentration of hydronium ion (H₃O⁺) will be:

[H₃O⁺] = $10^{-pH}$

[H₃O⁺] = $10^{-8.5}$

[H₃O⁺] = 3.162 × 10⁻⁹ moles / liter

3 0

3 years ago

Read 2 more answers

SOVA2 [1]

This problem is providing us with the recommended maintenance dose of penicillin for children as 1.0 mg/kg/hr by injection. Thus, the delivery rate for a 40-pound child is required, if 10 mL of a 25 mg/mL solution of penicillin is added to a 100-mL bottle of saline. At the end, the result is 8.0 mL/hr:

<h3>Dimensional analysis:</h3>

In chemistry, dimensional analysis allows us to obtain a specific result given relevant information about it. Although a formula is not always provided, one can use the units as a reference for the calculations.

For example, this problem asks for the rate, in mL/hr, at which a child gets this dose, so the first step will be to get the mass of the child in kilograms:

$40 lb*\frac{0.4536kg}{1lb}= 18.144kg$

Next, we calculate the rate at which the penicillin is delivered to this child:

$1.0\frac{mg}{kg*hr} *18.144kg=18.144\frac{mg}{hr}$

After that, we calculate the total mass of penicillin that is delivered:

$10mL*25\frac{mg}{mL} =250 mg$

And get the new concentration once it is diluted to 100 mL:

$\frac{250mg}{10mL+100mL}=2.27\frac{mg}{mL}$

And finally, we combine the mg/hr with the mg/mL to get the result in mL/hr as required:

$18.144\frac{mg}{hr} *\frac{1mL}{2.27mg}\\ \\=8.0\frac{mL}{hr}$

Learn more about dimensional analysis: brainly.com/question/10874167

5 0

2 years ago

3. Determine the pH of each of the following solutions. (Hint: See Sample Problem B.) a. 1.0 x 10-2 M HCI c. 1.0 x 10-MHI b. 1.0

densk [106]

Answer:

a. pH = 2 b. pH = 3 c. pH = 1 d. Unanswerable

Explanation:

pH = -log[H+] OR pH = -log{H3O+]

and inversely

pOH = -log[OH-]

1. Determine what substance you are working with, (acid/base)

2. Determine whether or not that acid or base is strong or weak.

a. 1.0 x 10^-2M HCl

HCl is a strong acid, therefore it will dissociate completely into H+ and Cl- with all ions going to the H+, therefore, the concentration of HCl and concentration of H+ are going to be equal, meaning we simply take the negative logarithm of the concentration of HCl and that would equal pH

pH = -log[H+]

pH = -log(1.0x10^-2)

pH = 2

b. 1.0 x 10^-3M HNO3

HNO3 like part a, is a strong acid, therefore it would simply require you to take the negative logarithm of the concentration of the compound itself, to find its pH.

pH = -log[H+]

pH = -log(1.0 x 10^-3)

pH = 3

c. 1.0 x 10^-1M HI

Like the previous parts, HI is a strong acid

pH = -log[H+]

pH = -log(0.10)

pH = 1

d. HB isn't an element, nor is it a compound so that would be unanswerable.

3 0

3 years ago

How many orbitals are in Phosphorus