Can someone's help me with this

When the outer electrons of substances are removed, they become statically charged.. . True. False.

elena55 [62]

It is true that when the outer electrons of substances are removed, they become statically charged. The correct answer is True.

6 0

3 years ago

What is the mole fraction, X, of solute and the molality, m (or b), for an aqueous solution that is 15.0% NaOH by mass?

GalinKa [24]

Hello!

a) The mole fraction of solute of a 15% NaOH aqueous solution can be calculated in the following way:

First, we have to assume that we have 100 grams of solution. This will simplify the calculations.

Now, we know that this solution has 15 grams of NaOH and 85 grams of water. We can calculate the number of moles of each one in the following way:

$molesNaOH= 15 g NaOH*\frac{1molNaOH}{39,997 g NaOH}=0,3750 moles NaOH \\ \\ moles H_2O=85 gH_2O* \frac{1 mol H_2O}{18 g H_2O}=4,7222 moles H_2O$

To finish, we calculate the mole fraction by dividing the moles of NaOH between the total moles:

$X_{NaOH}= \frac{moles NaOH}{total moles}= \frac{0,3750 moles NaOH}{0,3750 moles NaOH+4,7222 molesH_2O} =0,073$

So, the mole fraction of NaOH is 0,073

b) The molality (moles NaOH/ kg of solvent) of a 15% NaOH aqueous solution can be calculated in the following way:

First, we have to assume that we have 100 grams of solution. This will simplify the calculations.

Now, we know that this solution has 15 grams of NaOH and 85 grams (0,085 kg) of water. We can calculate the moles of NaOH in the following way:

$molesNaOH= 15 g NaOH*\frac{1molNaOH}{39,997 g NaOH}=0,3750 moles NaOH$

Now, we apply the definition of molality to calculate the molality of the solution:

$mNaOH= \frac{moles NaOH}{kg_{solvent}}= \frac{0,3750 moles NaOH}{0,085 kg H_2O}=4,41 m$

So, the molality of this solution is 4,41 m

Have a nice day!

4 0

3 years ago

Which of these is an example of physical change?

lana [24]

A. Boiling water is an example of physical change, whereas digesting food, breaking glass, and shoveling snow are not.

6 0

2 years ago

Your chemistry teacher empties her dehumidifier once a day if The composite of the tank is 2 gallons determine how many molecule

Natasha_Volkova [10]

Given data:

Amount of water collected in the dehumidifier= 2 gallons

Time taken to collect 2 gallons = 1 day

Calculation

Step1 : Find the mass of 2 gallons of water

1 gallon = 3.79 L

Therefore, 2 gallons = 2 gallon * 3.79 L/1 gallon = 7.58 L

Density of water = 1 kg/L

Therefore, Mass of 7.58 L water = Density * Vol = 1 * 7.58 = 7.58 kg = 7580 g

Step 2: Convert mass of water to molecules

1 mole of water = 18 g = 6.023 *10^23 molecules

therefore, 7580 g contains: 6.023 * 10^23 * 7580/18 = 2.536 *10^26 molecules

Step 3: Calculate the molecules of water collected/millisecond

Now,

2.536*10^26 water molecules are collected in 1 day

1 day = 24 hrs * 60 min * 60 sec = 86400 sec

10^-3 sec = 1 millisec

therefore, 86400 sec = 1 millisec * 86400 sec/10^-3 sec = 8.64 * 10^7 millisec

Thus water molecules collected/millisec = 2.536*10^26/8.64*10^7

= 2.935 *10^32 molecules/millisec

6 0

2 years ago

Read 2 more answers

In what way are all sound waves and light waves similar?

SashulF [63]

So sound waves, and light waves. Well they are both waves, they can be reflected/refracted.

5 0

3 years ago

Read 2 more answers