PLEASe help I will count you brainless please :) what element is this?

Given 0.02 of KF, how many liters of solution are needed to make a 7.2 solution?

Dmitry_Shevchenko [17]

Answer:

1/360

Explanation:

let x = liters

molarity=moles of solute/liters of solution, 7.2=0.02/x or 7.2=(1/50)(1/x), 7.2(50)=(1/x), 360(x)=1, x=1/360

7 0

2 years ago

A sample of water contains 5.24x10^22 molecules. How many moles are in this sample?

Helga [31]

Answer:

0.087 moles of water

Explanation:

Given data:

Number of molecules of water = 5.24×10²² molecules

Number of moles of water = ?

Solution:

The given problem will solve by using Avogadro number.

1 mole = 6.022 × 10²³ molecules of water

5.24×10²² molecules × 1 mol / 6.022 × 10²³ molecules

0.87×10⁻¹ mol

0.087 mol

Avogadro number:

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance. The number 6.022 × 10²³ is called Avogadro number.

8 0

2 years ago

Complete combustion of 5.90 g of a hydrocarbon produced 18.8 g of CO2 and 6.75 g of H2O.

Inessa05 [86]

First we have to find moles of C:
Molar mass of CO2:
12*1+16*2 = 44g/mol
(18.8 g CO2) / (44.00964 g CO2/mol) x (1 mol C/ 1 mol CO2) =0.427 mol C
Molar mass of H2O:
2*1+16 = 18g/mol
As there is 2 moles of H in H2O,
So,

(6.75 g H2O) / (18.01532 g H2O/mol) x (2 mol H / 1 mol H2O) = 0.74mol H 

Divide both number of moles by the smaller number of moles: 
As Smaaler no moles is 0.427:
So,
Dividing both number os moles by 0.427 :
(0.427 mol C) / 0.427 = 1.000 
(0.74 mol H) / 0.427 = 1.733 

To achieve integer coefficients, multiply by 2, then round to the nearest whole numbers to find the empirical formula:
C = 1 * 2 = 2
H = 1.733 * 2 =3.466
So , the empirical formula is C2H3

4 0

2 years ago

Read 2 more answers

Who asks scientific questions?

Katena32 [7]

Answer:

I think its c I'm not that sure tho

6 0

2 years ago

Read 2 more answers

g 304 mL of a 0.36 M potassium hydroxide solution is added to 341 mL of a 0.51 M lithium hydroxide solution. Calculate the pOH o

Liono4ka [1.6K]

Answer:

pOH = 0.36

Explanation:

Both potassium hydroxide and lithium hydroxide solutions are strong bases, so you assume 100% dissociation.

1. Potassium hydroxide solution, KOH

Volume, V = 304 mL = 0.304 liter

Molarity, M = 0.36 M

number of moles, n = M × V = 0.36M × 0.304 liter = 0.10944 mol

1 mole of KOH produces 1 mol of OH⁻ ion, thus the number of moles of OH⁻ is 0.10944

2. LIthium hydroxide, LiOH

Volume, V = 341 mL = 0.341 liter

Molarity, M = 0.51 M

number of moles, n = M × V = 0.341 liter × 0.51 M = 0.17391 mol

1mole of LiOH produces 1 mol of OH⁻ ion, thus the number of moles of OH⁻ is 0.17391

3. Resulting solution

Number of moles of OH⁻ ions = 0.10944 mol + 0.17391 mol = 0.28335 mol

Volume of solution = 0.304 liter + 0.341 liter = 0.645 liter

Molar concentration = 0.28335 mol / 0.645 liter = 0.4393 M

4. pOH

$pOH=-\log [OH^-]=-\log (0.439)=0.36$ ← answer

5 0

2 years ago