How can mass and energy behave in an open system

How many grams of tris (mw 121.1) would you need to prepare 100 ml of a 100 mm tris solution? _________ grams?

Tems11 [23]

Molarity = (Mass/ molar mass) x (1/ volume of solution in Litres)

Mass = Molarity x molar mass x volume of solution in Litres

Molarity of Tris = 100 mM = 0.1 M

volume of Tris sol. = 100 mL = 0.1 L

molar mass of Tris = 121.1 g/mol

Hence,

mass of Tris = Molarity of Tris x molar mass ofTris x volume of Tris solution

= 0.1 M x 121.1 g/mol x 0.1 L

= 1.211 g

mass of Tris = 1.211 g

7 0

3 years ago

Using the thermodynamic information in the ALEKS Data tab, calculate the boiling point of titanium tetrachloride . Round your an

ddd [48]

Answer:

The boiling point is 308.27 K (35.27°C)

Explanation:

The chemical reaction for the boiling of titanium tetrachloride is shown below:

Ti $Cl_{4(l)}$ ⇒ Ti $Cl_{4(g)}$

ΔH° $_{f}$ (Ti $Cl_{4(l)}$ ) = -804.2 kJ/mol

ΔH° $_{f}$ (Ti $Cl_{4(g)}$ ) = -763.2 kJ/mol

Therefore,

ΔH° $_{f}$ = ΔH° $_{f}$ (Ti $Cl_{4(g)}$ ) - ΔH° $_{f}$ (Ti $Cl_{4(l)}$ ) = -763.2 - (-804.2) = 41 kJ/mol = 41000 J/mol

Similarly,

s°(Ti $Cl_{4(l)}$ ) = 221.9 J/(mol*K)

s°(Ti $Cl_{4(g)}$ ) = 354.9 J/(mol*K)

Therefore,

s° = s° (Ti $Cl_{4(g)}$ ) - s°(Ti $Cl_{4(l)}$ ) = 354.9 - 221.9 = 133 J/(mol*K)

Thus, T = ΔH° $_{f}$ /s° = [41000 J/mol]/[133 J/(mol*K)] = 308. 27 K or 35.27°C

Therefore, the boiling point of titanium tetrachloride is 308.27 K or 35.27°C.

5 0

2 years ago

List first thirty elements with their valences

lbvjy [14]

Element Atomic Number Valency

Valency of Hydrogen 1 1

Valency of Helium 2 0

Valency of Lithium 3 1

Valency of Beryllium 4 2

Valency of Boron 5 3

Valency of Carbon 6 4

Valency of Nitrogen 7 3

Valency of Oxygen 8 2

Valency of Fluorine 9 1

Valency of Neon 10 0

Valency of Sodium (Na) 11 1

Valency of Magnesium (Mg) 12 2

Valency of Aluminium 13 3

Valency of Silicon 14 4

Valency of Phosphorus 15 3

Valency of Sulphur 16 2

Valency of Chlorine 17 1

Valency of Argon 18 0

Valency of Potassium (K) 19 1

Valency of Calcium 20 2

Valency of Scandium 21 3

Valency of Titanium 22 4

Valency of Vanadium 23 5,4

Valency of Chromium 24 2

Valency of Manganese 25 7, 4, 2

Valency of Iron (Fe) 26 2, 3

Valency of Cobalt 27 3, 2

Valency of Nickel 28 2

Valency of Copper (Cu) 29 2, 1

Valency of Zinc 30 2

5 0

2 years ago

What evidence is there that marker ink is a mixture

zheka24 [161]

Ink can be separated into black and other color pigments. This can be done on filter paper by dotting the marker just above the edge and adding ethyl alcohol, which drags the pigments separately across the paper.

5 0

2 years ago

An element's most stable ion forms an ionic compound with bromine, having the formula XBr. If the ion of element X has a mass nu

earnstyle [38]

Answer:

The element is Rubidium . The ion only loss one electron to make the electron 36 . But the proton number(atomic number) is 37. The chemical compound should RbBr

X = Rubidium(Rb)

Explanation:

The ion of element X has a mass number of 85 and electron of 36. An elements is charge if it either loss or receive electron. Base on the charge the ion has loss electron. Bromine usually possess a negatively charge ion. That makes the X electron a positively charge ion.

proton number = Atomic number

Proton number = electron number when not charged

Mass number = proton number + neutron number

Proton is usually same number with the electron to make the element neutral. But when the atom is charge the atom usually loss or gain electron.

In this case, the atom X loss one electron thereby reducing the electron number to 36 . Recall, the electron is equal to proton only if the atom is uncharged. This means the proton number should be 37 as one electron was loss.

Element with proton number(atomic number) of 37 is rubidium. It is an alkali metal that is very reactive.

8 0

3 years ago