Ask question

Ask question

All categories

3 years ago

15

If the melting point of a certain amount of a solid is 50 degrees, what is the melting point of half that amount of the solid? 5

0 degrees 25 degrees 0 degrees 100 degrees

1 answer:

borishaifa [10]3 years ago

4 0

The answer is 25 degrees.

You might be interested in

Write the lewis structure for mgi2. draw the lewis dot structure for mgi2. include all lone pairs of electrons.

viktelen [127]

Lewis Structure is drawn in following steps,

1) Calculate Number of Valence Electrons:

# of Valence electrons in Mg = 2
# of Valence electrons in I     = 7
# of Valence electrons in I     = 7
---------
Total Valence electrons = 16

2) Draw Mg as a central atom surround it by two atoms of Iodine.

3) Connect each Iodine atom to Mg, and subtract two electrons per bond. In this case we will subtract 4 electrons from total valence electrons. i.e.

Total Valence electrons 16
- Four electrons - 4
----------
    12

4) Now start adding the remaining 12 electrons on more electronegative atoms i.e. Iodine.

The final lewis structure formed is as follow,

4 0

3 years ago

What is the mass of 2.25 x 10^25 atoms of lead

NemiM [27]

Answer: the amount of a substance that contains 6.02 x 1023 respective particles of that

substance

Avogadro’s number: 6.02 x 1023

Molar Mass: the mass of one mole of an element

CONVERSION FACTORS:

1 mole = 6.02 x 1023 atoms 1 mole = atomic mass (g)

Try:

1. How many atoms are in 6.5 moles of zinc?

6.5 moles 6.02 x 1023 atoms = 3.9 x 1024 atoms

1 mole

2. How many moles of argon are in a sample containing 2.4 x 1024 atoms of argon?

2.4 x 1024 atoms of argon 1 mole = 4.0 mol

6.02 x 1023 atoms

3. How many moles are in 2.5g of lithium?

2.5 grams Li 1 mole = 0.36 mol

6.9 g

4. Find the mass of 4.8moles of iron.

4.8 moles 55.8 g = 267.84 g = 270g

1 mole

MOLE PARTICLES

(ATOM)

MASS

(g)

1 mole = molar

mass

(look it up on

the PT!)

1 mole =

6.02 x 1023

atoms

1 mole = 6.02 x 1023 atoms 1 mole = atomic mass (g)

Two Step Problems:

1. What is the mass of 2.25 x 1025 atoms of lead?

2.25 x 1025 atoms of lead 1 mole 207.2g = 7744.19g = 7740g

6.02 x 1023 atoms 1 mole

2. How many atoms are in 10.0g of gold?

10 g gold 1 mole 6.02 x 1023 atoms = 3.06 x 1022 atoms

197.0g 1 mole

PRACTICE PROBLEMS:

1. How many moles are equal to 625g of copper?

625g of copper 1 mol = 9.77 mol Cu

64 g Cu

2. How many moles of barium are in a sample containing 4.25 x 1026 atoms of barium?

4.25 x 1026 atoms of barium 1 mol = 706 mol

6.02 x 1023 atoms

3. Convert 2.35 moles of carbon to atoms.

2.35 moles 6.02 x 1023 atoms = 1.41 x 1024 atoms

1 mole

4. How many atoms are in 4.0g of potassium?

4.0 g 1 mole 6.02 x 1023 atoms = 6.2 x 1022 atoms

39.1 g 1 mole

1 mole = 6.02 x 1023 atoms 1 mole = atomic mass (g)

5. Convert 9500g of iron to number of atoms in the sample.

9500 g Fe 1 mole 6.02 x 1023 atoms = 1.0 x 1026 atoms

55.8g 1 mole

6. What is the mass of 0.250 moles of aluminum?

0.250 moles 27.0g = 6.75 g Al

1 mole

7. How many grams is equal to 3.48 x 1022 atoms of tin?

3.48 x 1022 atoms 1 mole 118.7g = 6.86 g Sn

6.02 x 1023 atoms 1 mole

8. What is the mass of 4.48 x 1021 atoms of magnesium?

4.48 x 1021 atoms 1 mole 24.3g = 0.181 g Mg or 1.8 x 10-1

6.02 x 1023 atoms 1 mole

9. How many moles is 2.50kg of lead?

2.50kg 1000 g 1 mol = 12.1 mol

1 kg 207.2 g

10.Find the mass, in cg, of 3.25 x 1021 atoms of lithium.

3.25 x 1021 atoms 1 mol 6.9g 100cg = 3.7

Explanation:

5 0

3 years ago

Choose the aqueous solution below with the highest freezing point. These are all solutions of nonvolatile solutes and you should

GrogVix [38]

Answer:

0.200 m K3PO3

Explanation:

Let us remember that the freezing point depression is obtained from the formula;

ΔTf = Kf m i

Where;

Kf = freezing point constant

m = molality

i = Van't Hoff factor

The Van't Hoff factor has to do with the number of particles in solution. Let us consider the Van't Hoff factor for each specie.

0.200 m HOCH2CH2OH - 1

0.200 m Ba(NO3)2 - 3

0.200 m K3PO3 - 4

0.200 m Ca(CIO4)2 - 3

Hence, 0.200 m K3PO3 has the greatest van't Hoff factor and consequently the greatest freezing point depression.

8 0

2 years ago

El pH de una solución acuosa 10^-14 M de ácido acético, a 25°C, es igual a, teniendo en cuenta que Ke = 1.76x10^-5

frez [133]

Answer:

$pH=14$

Explanation:

Hola!

En este caso, consideramos que la disociación de ácido acético ocurre:

$CH_3COOH\rightarrow CH_3COO^-+H^+$

Así, mediante la solución del equilibrio ácido, podemos calcular la concentración de iones hidronio que posteriormente sirven para calcular el pH de la solución, por tal razón, debemos calcular el equilibrio dada la constante de equilibrio y por medio de la ley de acción de masas en términos del cambio $x$ como cualquier problema de equilibrio:

$Ke=\frac{CH_3COO^-][H^+]}{[CH_3COOH]}\\\\1.76x10^{-5}=\frac{x*x}{1x10^{-14}M-x}$

Resolviendo para $x$ , tenemos $x=0.999x10^{-14}$

Así, la concentración de hidrógeno es igual a x, por lo que el pH:

$pH=-log([H^+])=-log(0.999x10^{-14})\\\\pH=14$

Dicho valor tiene sentido desde que la concentración de hidrógeno es casi despreciable, por lo que se puede asumir que tiende a ser básica.

Saludos!

5 0

3 years ago

Read 2 more answers

The scale reads "16.121 grams", which number(s) is/are "estimated by the scale?

luda_lava [24]

Answer:

See explanation

Explanation:

There are different kinds of analytical balances that read the mass of objects weighed in them to one, two, three or four decimal places as the case may be.

Most common analytical balances read the mass of objects to two or three decimal places hence the last 1 after the decimal point are likely to be approximated.

Hence, the scale may read 16.12 as the case may be.

8 0

3 years ago