What are the three ways that an object can interact with a static field?

Is dissolving salt a chemical change or physical change and why?

Firlakuza [10]

It's a physical change because the composition of the salt hasn't change. Only the change in substance/form has occured. To tell if something has undergone physical change is:

• Melting

• Boiling

• Freezing

• Condensing

• Breaking

• Bending

• Dissolving

• Molecules can change motion and proximity

To tell if something changed chemically:

• Molecules rearrange with other molecules to make new substance

• Can be production of flames

• Color change

• Bubbling/fizzing

• Temp. change

• change in composition

4 0

3 years ago

What is the concentration (m) of sodium ions in 4.57 l of a.847 m na3p solution?

drek231 [11]

A group of environmentalists were discussing the benefits and drawbacks associated with using fossil fuels. Which argument best fits the conversation?
Fossil fuels are cheaper than alternative forms of energy.Fossil fuel reserves will never be depleted.Fossil fuels are easily renewed. Fossil fuel use does not affect the environment.

8 0

3 years ago

What is the mass of water necessary to generate 11.2 L of hydrogen gas if calcium metal reacts with water at standard temperatur

12345 [234]

Answer:

The mass of water is 18 g

Explanation:

The reaction of calcium with water can be represented in the equation below:

Ca + 2H₂O --------->Ca(OH)₂ +H₂

1 Mole of gas at STP = 22.4L

From the displacement reaction above, calculate the mass of water that will produce 22.4L of hydrogen gas at STP.

Mass of 2H₂O = 2(2x1 + 16) = 2X18 = 36 g/mol

Using proportional analysis;

36 g of 2H₂O produced 22.4 L of H₂, then

what mass of 2H₂O will produce 11.2L of H₂ ?

Mathematically,

22.4 L ----------------------------------> 36g

11.2 L -----------------------------------> ?

Cross and multiply, to obtain the expression below

= (11.2 X 36)/22.4

= 18 g

Therefore, the mass of water is 18 g

5 0

3 years ago

Calculate the molecular weight of a substance. In which the solution of this substance in the water has a concentration of 7 per

Eduardwww [97]

Answer : The molecular weight of a substance is 157.3 g/mol

Explanation :

As we are given that 7 % by weight that means 7 grams of solute present in 100 grams of solution.

Mass of solute = 7 g

Mass of solution = 100 g

Mass of solvent = 100 - 7 = 93 g

Formula used :

$\Delta T_f=i\times K_f\times m\\\\T_f^o-T_f=k_f\times\frac{\text{Mass of substance(solute)}\times 1000}{\text{Molar mass of substance(solute)}\times \text{Mass of water(solvent)}}$

where,

$\Delta T_f$ = change in freezing point

$T_f^o$ = temperature of pure water = $0^oC$

$T_f$ = temperature of solution = $-0.89^oC$

$K_f$ = freezing point constant of water = $1.86^oC/m$

m = molality

Now put all the given values in this formula, we get

$(0-(-0.89))^oC=1.86^oC/m\times \frac{7g\times 1000}{\text{Molar mass of substance(solute)}\times 93g}$

$\text{Molar mass of substance(solute)}=157.3g/mol$

Therefore, the molecular weight of a substance is 157.3 g/mol

7 0

3 years ago

If two atoms are bonded with a bond energy of 87 kJ, what must be done to break the bond?

SSSSS [86.1K]

I would say the energy has to be decreased by 87 kj because the bonding is held together by 87 kj so removing that should prevent the bonding from taking place or reverse it I believe. In other words, a certain amount of energy is required to hold the bond together and in the absence of that energy, the bonding will not take place.

7 0

4 years ago