This substance should never be used to put out a petrol or oil fire

How many milligrams of magnesium reacts with excess HCl to produce 31.2 mL of hydrogen gas at 754 Torr and 25.0℃.

Ivanshal [37]

Answer:

There will react 30.9 milligrams of magnesium

Explanation:

Step 1: Data given

Volume of hydrogen = 31.2 mL

Pressure = 754 torr = 754/760 = 0.992 atm

Temperature = 25.0 °C = 298 Kelvin

Step 2: The balanced equation

Mg + 2HCl → MgCl2 + H2

Step 3: Calculate moles of H2

p*V = n*R*T

⇒ with p = the pressure of H2 = 0.992 atm

⇒with V = the volume of H2 = 31.2 mL = 0.0312 L

⇒ with n = the moles of H2 = TO BE DETERMINED

⇒ with R = the gas constant = 0.08206 L*atm/K*mol

⇒ with T= the temperature = 25.0 °C = 298 Kelvin

n = (p*V)/(R*T)

n = (0.992*0.0312)/(0.08206*298)

n = 0.00127 moles

Step 4: Calculate moles of Mg

For 1 mol of Mg we need 2 moles of HCl to produce 1 mol of MgCl2 and 1 mol of H2

For 0.00127 moles of H2 we need 0.00127 moles of Mg

Step 5: Calculate mass of Mg

Mass of Mg = moles of Mg * molar mass of Mg

Mass of Mg = 0.00127 moles * 24.3 g/mol

Mass of Mg = 0.0309 grams = 30.9 mg of Mg

There will react 30.9 milligrams of magnesium

3 0

2 years ago

A high speed train travels 176 miles in 7 hours. What is the speed of the train

umka21 [38]

Answer:

25 mph

Explanation:

So we have to find the unit rate, or you could use the DTS triangle, but both say you have to divide, so our equation is:

176 ÷ 7 = 25.14

But I'm going to round that

So the train is traveling at 25 mph

hope this helps:/

4 0

2 years ago

A sample of salt (sodium chloride) is placed on the tip of a platinum wire. When the sample is heated on blue flame the flame tu

gulaghasi [49]

So platinum is a transition metal. In general transition metals are reducers, which means they can give the electrons they have, to the sodium atoms. Also in chemistry we look at sub orbitals rather that shells(2,8,8). So due to the energy from heat, the d orbital split as electrons move to a higher energy level. Some of the electrons are given to the sodium ions and therefore the flame changes colour to yellow.
The excitation of the electrons is caused by them getting energy and so moving up an energy level. This energy is released and the electron returns to it's original state. The energy released, however, does not release in the same direction, but in different/various directions. Therefore the colour of the light changes as some energy is released in the surrounding.

8 0

3 years ago

Chlorine reacts with sodium and with hydrogen.

Sonbull [250]

Answer:

Sodium Chloride has Ionic bond while Hydrogen Chloride has covalent bond.

Explanation:

Na has 11 electrons (2, 8, 1) and need to give away 1 electron to be stable

Cl has 17 electrons ( 2, 8, 7) and needs 1 electron to be stable.

Na transfers 1 electron to CL to form Ionic bond.

While

Hydrogen has 1 electron and shares with Chlorine to be stable.

Covalent bond involves sharing.

3 0

3 years ago

Which property do metalloids share with non metals?

mamaluj [8]

Answer:

their ability to conduct heat and electricity.

Explanation:

6 0

3 years ago