How many different elements have scientists discovered? 12, 112, 118, or more than 500?

A 12.0g sample of a substance requires 50.9 J to raise its temperature by 6.00 c. What is it’s specific heat

horsena [70]

$\qquad\qquad\huge\underline{{\sf Answer}}$

Let's find the specific heat of sample using given formula :

$\qquad \tt \dashrightarrow \:Q = m \: s \triangle T$

where,

Q = heat transfer

m = mass

S = specific heat

$\tt \triangle T$ = change in temperature

$\qquad \tt \dashrightarrow \:50.9 = 12 \times \: s \times 6$

$\qquad \tt \dashrightarrow \:s = \dfrac{50.9}{72}$

$\qquad \tt \dashrightarrow \:s = 0.707 \:$

Therefore, specific heat of that substance is 0.707 J/g°C

7 0

2 years ago

Which set of numbers gives the correct possible values of I for n = 2?

Marysya12 [62]

Answer:

0,1

Explanation:

There are four quantum numbers:

Principal quantum number (n)

Azimuthal quantum number (l)

Magnetic quantum number (ml)

Spin quantum number (ms)

All these four quantum numbers gives complete information about an electron like its spin, shells, subshells and orbitals.

For example:

If n=2 than possible sets of quantum numbers are:

Azimuthal quantum number (l)

The azimuthal quantum number describe the shape of orbitals. Its value for s, p, d, f... are 0, 1, 2, 3. l= n-1

(n-1)

2-1 = 1

For n=2 there are two subshell s and p.

s = 0

p= 1

Magnetic quantum number (ml)

It describe the orientation of orbitals. Its values are -l to +l. For l=1 the ml will be -1 0 +1

Spin quantum number (ms)

The spin quantum number tells the spin of electron either its clock wise (+1/2) or anti clock wise (-1/2).

If the electron is added in full empty orbital its spin will be +1/2 because it occupy full empty. If electron is already present and another electron is added then its spin will be -1/2.

4 0

3 years ago

Solid mixture contains MgCl2 and NaCl. When 0.5000 g of this solid is dissolved in enough water to form 1.000 L of solution, the

aksik [14]

Answer:

83,40 (w/w) %

Explanation:

The osmotic pressure (π) is defined as:

π = iMRT

Where i is Van't Hoff factor (3 for MgCl₂ and 2 for NaCl), M is molarity, R is gas contant (0,082atmL/molK) and T is temperature (298,15K)

iM = π / RT

iM = 0,01607mol/L

It is possible to write:

3x+2y = 0,01607mol/L (1)

Where x are moles of MgCl₂ and y moles of NaCl.

-M = moles of each compund because M is molarity (moles/L) and there is 1,000L-

Knowing molar mass of MgCl₂ is 95,2 g/mol and for NaCl is 58,44g/mol:

x×95,211 + y×58,44 = 0,5000g (2)

Replacing (2) in (1):

3x+2(0,0086 - 1,629x) = 0,01607mol/L

-0,258x = -0,00113

x = 0,004380 moles of MgCl₂

In grams:

0,004380 moles of MgCl₂×(95,211g/mol) = 0,417g of MgCl₂

Mass percent is:

(0,4170g of MgCl₂/0,5000g of solid) ×100 = 83,40 (w/w) %

I hope it helps!

4 0

3 years ago

What is made when a salt is dissolved in water?

Xelga [282]

Answer:

D. A solution.

Explanation:

"Water molecules pull the sodium and chloride ions apart, breaking the ionic bond that held them together. After the salt compounds are pulled apart, the sodium and chloride atoms are surrounded by water molecules, as this diagram shows. Once this happens, the salt is dissolved, resulting in a homogeneous solution."

3 0

3 years ago

To test the purity of sodium bicarbonate, you dissolve a 3.50g sample in water and add sulfuric acid. if 1.04g of carbon dioxide

Andrews [41]

Answer is: the percent purity of the sodium bicarbonate is 56.83 %.

1. Chemical reaction: 2NaHCO₃ + H₂SO₄ → 2CO₂ + 2H₂O + Na₂SO₄.

2. m(NaHCO₃) = 3.50 g

n(NaHCO₃) = m(NaHCO₃) ÷ M(NaHCO₃).

n(NaHCO₃) = 3.50 g ÷ 84 g/mol.

n(NaHCO₃) = 0.042 mol.

3. From chemical reaction: n(NaHCO₃) : n(CO₂) = 1 : 1.

n(CO₂) = 0.042 mol.

m(CO₂) = 0.042 mol · 44 g/mol.

m(CO₂) = 1.83 g.

4. the percent purity = 1.04 g/1.83 g ·100%.

the percent purity = 56.8 %.

8 0

3 years ago