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3 years ago

How many molecules of H2O are there in 1.0 g of H2O?

1 answer:

8 0

Molar mass H₂O = 18.0 g/mol

number of moles :

1.0 / 18.0 => 0.055 moles

1 mole -------------- 6.02 x 10²³ molecules
0.055 moles -------- ? molecules

molecules = 0.055 x ( 6.02 x 10²³) / 1

molecules = 3.311x10²² / 1

= 3.311 x 10²² molecules

hope this helps!

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You are given a solution that is 518 mM lactose. You need to make up 4.5 L of 16.7 mM solution. What volume do you need to trans

OLga [1]

Answer:

The volume you need to transfer from the stock solution is 0.145 l

Explanation:

Since the number of moles of lactose in the volume of stock solution that you transfer will be the same as the number of moles of lactose in the final solution, you can use this expression:

number of moles in volume to transfer = number of moles in the final solution

Since number of moles = concentration * volume (if the concentration is expressed in molarity), then:

Ci * Vi = Cf * Vf

where:

Ci = concentration of the stock solution.

Vi = volume of the stock solution to be transferred.

Cf = concentration of the final solution

Vf = volume of the final solution

Then, replacing with the data:

518 mM * Vi = 16.7 mM * 4.5 l

Vi = 16.7 mM * 4.5 l / 518 mM

Notice that any concentration unit can be used, as long as the units of the concentration of the stock and final solution are the same.

4 0

3 years ago

You can supply activation energy to begin a reaction by _____.

ehidna [41]

If I remember correctly, you would have to heat the reaction beaker over a burner..

I apologize if I'm wrong

3 0

3 years ago

Read 2 more answers

Help plz 50 points <3

Rufina [12.5K]

Answer:

I believe the answer is the last one answer D: Neutral elements

Explanation:

Ionic bonds are formed through the exchange of valence electrons between atoms, typically a metal and a nonmetal. ... Ionic compounds are typically neutral. Ionic compounds generally form between elements that are metals and elements that are nonmetals.

Hope this helps please mark brainliest :)

8 0

2 years ago

Drag the appropriate elements to their respective bins

kakasveta [241]

Well you have to do it because nobody on here has the answer choices but you

4 0

3 years ago

Read 2 more answers

Find the pH. What are the pH values for the following solutions? (a) 0.1 M HCl (b) 0.1 M NaOH (c) 0.05 M HCl (d) 0.05 M NaOH

slega [8]

Answer:

(a) $pH=1$

(b) $pH=1.3$

(d) $pH=12.7$

Explanation:

Hello,

In this case, we define the pH in terms of the concentration of hydronium ions as:

$pH=-log([H^+])$

Which is directly computed for the strong hydrochloric acid (consider a complete dissociation which means the concentration of hydronium equals the concentration of acid) in (a) and (c) as shown below:

(a)

$[H^+]=[HCl]=0.1M$

$pH=-log(0.1)=1$

(b)

$[H^+]=[HCl]=0.05M$

$pH=-log(0.05)=1.3$

Nevertheless, for the strong sodium hydroxide, we don't directly compute the pH but the pOH since the concentration of base equals the concentration hydroxyl in the solution:

$[OH^-]=[NaOH]$

$pOH=-log([OH^-])$

$pH=14-pOH$

Thus, we have:

(b)

$pOH=-log(0.1)=1\\pH=14-1=13$

(d)

$pOH=-log(0.05)=1.3\\pH=14-1.3=12.7$

Best regards.

5 0

3 years ago