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lutik1710 [3]
3 years ago
7

Which of the following describes a physical property? A) gunpowder explodes B) when two substances are mixed with a precipitate

forms C) a substance change colors when heated, but changes back when cooled D) a candle burns
Chemistry
2 answers:
never [62]3 years ago
6 0

Answer is: C) a substance change colors when heated, but changes back when cooled.

Physical property can be observed and measured without any changes in molecular composition. The same substance is present before and after the change.

Gunpowder explosion, precipitate form and candle burn are chemical change (chemical reaction combustion), because new substances are formed, the atoms are rearranged and the reaction is followed by an energy change (exothermic reaction because energy is released).

ValentinkaMS [17]3 years ago
5 0
The correct answer is C) A substance changes color when heated, but changes back when cooled. Hope this helps.
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Diatomic O2 can react with the element magnesium to form magnesium oxide (MgO). The balanced chemical equation is: 2Mg + O2 → 2M
tigry1 [53]

Answer:

We will expect 4 moles of MgO to be formed (option b).

Explanation:

Step 1: The balanced equation

2Mg + O2 → 2MgO

Step 2: Data given

Number of moles of Magnesium = 4 moles

Oxygen = in excess  → this means Magnesium is the limiting reactant

Magnesium will completely be consumed ( 4 moles). There will remain 0 moles.

For 2 moles of magnesium consumed, we need 1 mole of oxygen to produce 2 moles of MgO.

For 4 moles of magnesium, we need 4/2 = 2 moles of oxygen.

For 4  moles of magnesium, we will produce 4/1 = 4 moles of MgO

We will expect 4 moles of MgO to be formed (option b).

4 0
3 years ago
What does the host mean when he says that the acid has "donated a proton" to the water?
weqwewe [10]

Answer:

Option B

Explanation:

As Brønsted-Lowry theory states, acids are the ones that can donate protons.

When a proton is donated, it is released to become medium more acidic.

HCl is a strong acid.

HCl (l) + H₂O (l)  →  H₃O⁺ (aq) +  Cl⁻(aq)

These always reffers to strong acid where the dissociation is 100% completed.

In a weak acid, dissociation is not 100% complete, that's why we have an equilibrium.

HA (l) + H₂O (l)  ⇄  H₃O⁺ (aq) +  A⁻(aq)                   Ka

5 0
3 years ago
a scuba diver's tank contains 0.29g of oxygen compressed into volume of 2.3L. What is the pressure in the tank at 9C?
viva [34]

Answer:

The answer to your question is P = 0.18 atm

Explanation:

Data

mass of O₂ = 0.29 g

Volume = 2.3 l

Pressure = ?

Temperature = 9°C

constant of ideal gases = 0.082 atm l/mol°K

Process

1.- Convert the mass of O₂ to moles

                16 g of O₂ -------------------- 1 mol

                0.29 g of O₂ ----------------   x

                    x = (0.29 x 1)/16

                    x = 0.29/16

                    x = 0.018 moles

2.- Convert the temperature to °K

Temperature = 9 + 273 = 282°K

3.- Use the ideal gas law ro find the answer

              PV = nRT

-Solve for P

              P = nRT/V

-Substitution

              P = (0.018 x 0.082 x 282) / 2.3

-Simplification

              P = 0.416/2.3

-Result

               P = 0.18 atm

5 0
3 years ago
What is the formula of haso4​
ladessa [460]

Explanation:

The structure of Ferrarrisite Ca5(HAs O4)2(AsO4)2

8 0
3 years ago
I need Helpppp with my chemistry while we are out of school. I don't have a good teacher and he's not helping since it's his las
9966 [12]

Answer:

im not sure but I hope this helps

Explanation:

I believe the equivalents is just the moles reactant/moles limiting reactant

water has a denisty of 1 g/mL. 1 L is 1000 ml so there are 1000g/L.

the molar mass of water is 18g/mol if you use the Liters in the equation above you can find the number of grams present. divide this number you found by 18 to find the moles.

now take the amount of the other reactant given and divide it by its own molar mass. this will give you the number of moles of that reactant.

divide the moles of water by the moles of the reactant and that is the equivalent.

to find the normality you take this number and divide it by the number of liters.

5 0
3 years ago
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