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3 years ago

Which of the following statements are correct? Rewrite the incorrect statements to correct them.

1 answer:

7 0

A) true
b) false The atomic mass is never less than the atomic number.
c) this one is a bit tricky. For hydrogen, the atomic mass can equal the atomic number IF you are rounding the mass to the nearest whole number. That only works for hydrogen, though
d) false The larger the element, the more neutrons that are needed to keep the nucleus stable.
e) true
f) true

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A compound is known to contain 46.45% carbon and 20.61% oxygen by mass. each molecule contains two atoms of oxygen. what is the

pogonyaev

The compound is made of 2 oxygen molecules and the oxygen made of 20.61% its mass. If the molar mass of oxygen is 16, the molar mass of the compound will be:

2* oxygen* (16g/mol / oxygen) = 20.61% compound mass

compound mass= 32g/mol / 20.61%

compound mass= 155.26 g/mol

7 0

3 years ago

Calculate the molality of a 5.73 M ethanol (C2H5OH) solution whose density is 0.9327 g/mL.

Natalka [10]

Answer:

Molality = 8.57 m

Explanation:

Given data:

Molarity of solution = 5.73 M

density = 0.9327 g/mL

Molality of solution = ?

Solution:

Molality = moles of solute / kg of solvent.

Kg of solvent:

Mass of 1 L solution = density× volume

Mass of 1 L solution = 0.9327 g/mL × 1000 mL

Mass of 1 L solution = 932.7 g

Mass of solute:

Mass of 1 L = number of moles × molar mass

Mass = 5.73 mol × 46.068 g/mol

Mass = 263.97 g

Mass of solvent:

Mass of solvent = mass of solution - mass of solute

Mass of solvent = 932.7 g - 263.97 g

Mass of solvent = 668.73 g

In Kg = 668.73 /1000 = 0.6687 Kg

Molality:

Molality = number of moles of solute / mass of solvent in Kg

Molality = 5.73 mol / 0.6687 Kg

Molality = 8.57 m

4 0

3 years ago

A mass of 34.05 g of H2O(s) at 273 K is dropped into 185 g of H2O(l) at 310. K in an insulated container at 1 bar of pressure. C

kykrilka [37]

Answer:

The temperature of the system once equilibrium is reached, is 292 Kelvin

Explanation:

Step 1: Data given

Mass of H2O = 34.05 grams

⇒ temperature = 273 K

Mass of H2O at 310 K = 185 grams

Pressure = 1 bar = 0.9869 atm

Step 2: Calculate the final temperature

n(ice)*ΔH(ice fusion) + n(ice)*CP(H2O)(Tfinal- Ti,ice) + n(H20)*CP(H2O)*(Tfinal-Ti,H2O) = 0

Tfinal = [n(ice)*CP(ice)*Ti(ice) + n(H2O)*CP(H2O)*Ti(H20) - n(ice)*ΔH(ice fusion)] / [n(ice)*CP(ice) +n(H2O)*CP(H2O)]

⇒ with n(ice) = moles of ice = 34.05 grams / 18.02 g/mol = 1.890 moles

⇒ with CP(ice) = 75.3 J/K*mol

⇒ with Ti(ice) = the initial temperature of ice = 273 K

⇒ with n(H2O) = the moles of water = 185.0 grams / 18.02 g/mol = 10.27 moles

⇒ with CP(H2O) = CP(ice) = 75.3 J/K*mol

⇒ with Ti(H2O) = the initial temperature of the water = 310 K

⇒ with ΔH(ice, fusion) = 6010 J/mol

Tfinal = [1.890 moles * 75.3 J/K*mol * 273 + 10.27 mol * 75.3 J/K*mol * 310 K - 1.890 moles * 6010 J/mol] / [1.890 moles *75.3J/k*mol + 10.27 mol * 75.3 J/K*mol]

38852.541 + 239732.61 - 11358.9 = 267226.251

Tfinal= 291.8 ≈ 292 Kelvin

The temperature of the system once equilibrium is reached, is 292 Kelvin

8 0

4 years ago

El oxígeno y el azufre reaccionan con el cobre para formar óxido de cobre (CuO) y sulfuro de cobre (CuS), respectivamente. ¿Qué

oksian1 [2.3K]

Yes it need to be like that cause when it like that it like that

5 0

3 years ago

Plz answer these questions :

SSSSS [86.1K]

Answer: 2) see below

3) 2AgCl → 2Ag + Cl₂

Explanation:

Step 1: Crushing & Grinding CuFeS₂(s)→ CuFeS₂(s)

Step 2: Froth Flotation CuFeS₂(s)----> CuFeS₂ (l)

Step 3: Roasting 2CuFeS₂(l) + 3O₂(g) → 2FeO(s) + 2CuS(s) + 2SO₂(g)

Step 4: Converting matte to blister Cu₂S(l) + O₂(g) → 2Cu(l) + SO₂(g)

Step 5: Anode Casting Cu(l) → Cu(s)

Step 6: Electrolytic Refining Cu(s) → Cu(s)

Anode: Cu(s) → Cu₂ + (aq) + 2e-

Cathode: Cu2 + (aq) + 2e- → Cu(s)

see diagram below for illustration of steps

3) When silver chloride (solid) is exposed to sunlight, it decomposes into silver (solid) and chlorine (gas).

The equation is written as: $2AgCl_{(s)}\xrightarrow{\text{sunlight}}}2Ag_{(s)}+Cl_{2(g)}$

3 0

4 years ago