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2 years ago

Which of the following is a chemical change

Chemistry

2 answers:

Inessa [10]2 years ago

6 0

D because it’s changing the Material

gayaneshka [121]2 years ago

4 0

The answer is D :) good luck

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What is the atomic number? what is the atomic mass (a.k.a. mass number?

Oksanka [162]

Is the number of protons in an atom, or the total positive charge of an atom.

3 0

3 years ago

Which structures join with the cell’s membrane during exocytosis?

erma4kov [3.2K]

Answer:Exocytosis is also used to integrate new proteins into the cell membrane. In this process, the new protein is formed inside the cell, and migrates to phospholipid bilayer of the vesicle. The vesicle, containing the new protein as a part of the phospholipid bilayer, fuses with the cell membrane.

Explanation:

8 0

3 years ago

Predict whether the changes in enthalpy, entropy, and free energy will be positive or negative for the boiling of water, and exp

Sedbober [7]

Answer:

ΔH > 0; ΔS >0; ΔG = 0

Not spontaneous when T < 100 °C;

Equilibrium when T = 100 °C

Spontaneous when T > 100 °C

Step-by-step explanation:

The process is

H₂O(ℓ) ⇌ H₂O(g)

ΔH > 0 (positive), because we must add heat to boil water

ΔS > 0 (positive), because changing from a liquid to a gas increases the disorder

ΔG = 0, because the liquid-vapour equilibrium process is at equilibrium at 100 °C

ΔG = ΔH – TΔS

Both ΔH and ΔS are positive.

If T = 100 °C, ΔG =0. ΔH = TΔS, and the system is at equilibrium.

If T < 100 °C, the ΔH term will predominate, because T has decreased below the equilibrium value.

ΔG > 0. The process is not spontaneous below 100 °C.

If T > 100 °C, the TΔS term will predominate, because T has increased above the equilibrium value.

ΔG < 0. The process is spontaneous above 100 °C.

4 0

3 years ago

the elements in group 2 have similar chemical properties because each atom of these elements has the same

Vsevolod [243]

They have same electronic configuration

3 0

3 years ago

How many molecules of Mg3N2 (magnesium nitride) are formed when excess Mg (magnesium)

dybincka [34]

Explanation:

3Mg(s) + N2(g) = Mg3N2(s)

First check that the equation is balanced. In this case, it is.

Assuming that magnesium is the limiting reactant:

First find the molecular weight using the Periodic Table.

We find that the atomic mass of magnesium is approximately

24.3g, so the molecular weight is just 24.3g\mol

2. Next we need the mole to mole ratio. As there are 3

magnesiums for 1 magnesium nitride (shown by the coefficients), the

mole to mole ratio is 1 mol Mg3N2\3 mol Mg.

3. We need the amount of the substance, in grams. Since you have not

stated it in the question, I'll just do 10g AS AN EXAMPLE. Note that

depending on the amount, the LIMITING REAGENT MAY DIFFER.

4. Finally, we need the molecular weight of Mg3N2, which we can easily

calculate to be around 100.9\mol.

5. Putting this all together, we have 10gMg⋅ (mol Mg\24.3gMg)

(1mol Mg3N2\ 3mol Mg) (100.9g Mg3N2\mol Mg3N2)

the units will cancel to leave gMg3N2 (grams of magnesium nitride):

10gMg ⋅ (mol Mg\24.3gMg) (1mol Mg3N2\3mol Mg)

(100.9g Mg3N2\mol Mg3N2)

Doing the calculation yields approximately 13.84g.

Assuming that nitrogen is the limiting reactant:

Similarly, following the above steps but with 10g of nitrogen yields 36.04g

In conclusion, as we produce less amount of Mg3N2 when we assumed that Mg was the limiting reagent, magnesium is the limiting reagent and nitrogen is the excess.

Note: This is in THIS CASE, where we have 10g of both. The answer may vary depending on the amount of each substance.

7 0

2 years ago

Read 2 more answers