All categories

2 years ago

How many H2O molecules are there in 4.5 g of water (see picture)

Chemistry

1 answer:

White raven [17]2 years ago

7 0

Answer is B.
number of mole of water = 4.5/18 = 0.25mol
number of h2o molecules = 0.25 x 6.02 x 10^23 to get option B

You might be interested in

What type of bond is present between two atoms of tungsten in a light bulb filament?

stiks02 [169]

Answer:

ionic bonding

Explanation:

hope it helps

8 0

3 years ago

Which statement about the greenhouse effect is NOT true?

Archy [21]

Greenhouse gases were not historically present in the atmosphere.

7 0

3 years ago

Which ionic equation describes a redox reaction? A. Ag(+) + Cl- = AgCl B. 2H(+) + CO3(2-) = CO2 + H2O C. H(+) + OH(-) = H2O D. Z

Gennadij [26K]

Answer: The correct option is D. $Zn+Cu^{2+}\rightarrow Zn^{2+}+Cu$

Explanation:

Redox reaction is defined as the reaction in which oxidation and reduction take place simultaneously. It is known as the reaction in which the exchange of electrons takes place.

The oxidation reaction is defined as the reaction in which a chemical species loses electrons in a chemical reaction. It occurs when the oxidation number of a species increases.

A reduction reaction is defined as the reaction in which a chemical species gains electrons in a chemical reaction. It occurs when the oxidation number of a species decreases.

From the given ionic reactions:

$Zn+Cu^{2+}\rightarrow Zn^{2+}+Cu$

On the reactant side:

Oxidation number of Zn = 0

Oxidation number of Cu = +2

On the product side:

Oxidation number of Cu = 0

Oxidation number of Zn = +2

As the oxidation number of Zn is increasing from 0 to +2. Thus, it is getting oxidized. Similarly, the oxidation number of Cu is decreasing from +2 to 0. Thus, it is getting reduced. Therefore, forming a redox couple

Hence, the correct option is D. $Zn+Cu^{2+}\rightarrow Zn^{2+}+Cu$

6 0

3 years ago

How do plants affect the amount of carbon in Earth’s atmosphere?

kaheart [24]

Answer:

Explanation:

plants decrease the levels of carbon dioxide in the atmosphere due to the process of photosynthesis

6 0

2 years ago

A phosphate buffer solution (25.00 mL sample) used for a growth medium was titrated with 0.1000 M hydrochloric acid. The compone

AysviL [449]

Answer:

0,07448M of phosphate buffer

Explanation:

sodium monohydrogenphosphate (Na₂HP) and sodium dihydrogenphosphate (NaH₂P) react with HCl thus:

Na₂HP + HCl ⇄ NaH₂P + NaCl (1)

NaH₂P + HCl ⇄ H₃P + NaCl (2)

The first endpoint is due the reaction (1), When all phosphate buffer is as NaH₂P form, begins the second reaction. That means that the second endpoint is due the total concentration of phosphate that is obtained thus:

0,01862L of HCl× $\frac{0,1000mol}{L}$ = 1,862x10⁻³moles of HCl ≡ moles of phosphate buffer.

The concentration is:

$\frac{1,862x10^{-3}moles}{0,02500L}$ = 0,07448M of phosphate buffer

I hope it helps!

7 0

3 years ago