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3 years ago

Who was the First to use the term "Cell"?

Chemistry

1 answer:

Ierofanga [76]3 years ago

8 0

Answer:

Robert Hooke

Explanation:

He saw a series of walled boxes that reminded him of the tiny rooms, or cellula, occupied by monks.

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Will Florine react? will it combine with other elements?

Alexxx [7]

Fluorine is the most active chemical element, reacting with virtually every element. It even reacts with the noble gases at high temperatures and pressures. The noble gases, or Group 18 (VIIIA), also known as the inert gases, generally do not react with other elements.

Explanation:

5 0

4 years ago

What effect does adding a neutron have on the atoms identity

Sergeu [11.5K]

Neutrons don’t carry an electrical charge, meaning that adding or subtracting them from the nucleus will not change the electrical charge of the nucleus of an atom. But, adding/removing neutrons changes the mass of the nucleus. This is how isotopes are formed.

5 0

3 years ago

You need to prepare at 2.0 mL sample of a diluted drug for injection. The total amount of the drug to be injected in this 2.0 mL

pav-90 [236]

Answer:

a) The concentration of drug in the bottle is 9.8 mg/ml

b) 0.15 ml drug solution + 1.85 ml saline.

c) 4.9 × 10⁻⁵ mol/l

Explanation:

Hi there!

a) The concentration of the drug in the bottle is 294 mg/ 30.0 ml = 9.8 mg/ml

b) The drug has to be administrated at a dose of 0.0210 mg/ kg body mass. Then, the total mass of drug that there should be in the injection for a person of 70 kg will be:

0.0210 mg/kg-body mass * 70 kg = 1.47 mg drug.

The volume of solution that contains that mass of drug can be calculated using the value of the concentration calculated in a)

If 9.8 mg of the drug is contained in 1 ml of solution, then 1.47 mg drug will be present in (1.47 mg * 1 ml/ 9.8 mg) 0.15 ml.

To prepare the injection, you should take 0.15 ml of the concentrated drug solution and (2.0 ml - 0.15 ml) 1.85 ml saline

c) In the injection there is a concentration of (1.47 mg / 2.0 ml) 0.735 mg/ml.

Let´s convert it to molarity:

0.735 mg/ml * 1000 ml/l * 0.001 g/mg* 1 mol/ 15000 g = 4.9 × 10⁻⁵ mol/l

3 0

3 years ago

The following three equations represent reactions done in this lab exercise. Classify each reaction by their type. Note there ma

gulaghasi [49]

Answer: 1. $Cu(s)+4HNO_3(aq)rightarrow Cu(NO_3)_2(aq)+2NO_2(g)+2H_2O(l)$ : oxidation reduction

2. $Cu(NO_3)_2(aq)+2NaOH(aq)\rightarrow Cu(OH)_2(s)+2NaNO_3(aq)$ : precipitation

3. $CuO(s)+2HCl(aq)\rightarrow CuCl_2(aq)+H_2O(l)$ : Double displacement

Explanation:

Oxidation-reduction reaction or redox reaction is defined as the reaction in which oxidation and reduction reactions occur simultaneously.

Oxidation reaction is defined as the reaction in which a substance looses its electrons. The oxidation state of the substance increases.Reduction reaction is defined as the reaction in which a substance gains electrons. The oxidation state of the substance gets reduced.

$Cu(s)+4HNO_3(aq)rightarrow Cu(NO_3)_2(aq)+2NO_2(g)+2H_2O(l)$

Double displacement reaction is defined as the reaction where exchange of ions takes place. Double displacement reaction in which one of the product remain in solid form are represented by (s) after their chemical formulas. Such double displacement reaction are called as precipitation reaction.

$Cu(NO_3)_2(aq)+2NaOH(aq)\rightarrow Cu(OH)_2(s)+2NaNO_3(aq)$

Double displacement reaction is defined as the reaction where exchange of ions takes place.

$CuO(s)+2HCl(aq)\rightarrow CuCl_2(aq)+H_2O(l)$

Single displacement reaction is defined as the reaction where more reactive element displaces a less reactive element from its chemical reaction.

Decomposition reaction is defined as the reaction where a single substance breaks down into two or more simpler substances.

Synthesis/Combination reaction is defined as the reaction where substances combine in their elemental state to form a single compound.

6 0

3 years ago

The equilibrium constant, Kp, for the following reaction is 0.497 at 500K.PCl5(g) PCl3(g) + Cl2(g)If an equilibrium mixture of t

Anestetic [448]

<u>Answer:</u> The equilibrium partial pressure of chlorine gas is 0.360 atm

<u>Explanation:</u>

For the given chemical equation:

$PCl_5(g)\rightleftharpoons PCl_3(g)+Cl2(g)$

The expression of $K_p$ for above reaction follows:

$K_p=\frac{p_{Cl_2}\times p_{PCl_3}}{p_{PCl_5}}$

We are given:

$K_p=0.497\\p_{PCl_3}=0.651atm\\p_{PCl_5}=0.471atm$

Putting values in above equation, we get:

$0.497=\frac{p_{Cl_2}\times 0.651}{0.471}\\\\p_{Cl_2}=0.360atm$

Hence, the equilibrium partial pressure of chlorine gas is 0.360 atm

5 0

3 years ago