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(03.06 MC)

Why is a depletion of the ozone layer harmful? (2 points)

Select one:
a. It increases chlorofluorocarbons (CFCs).
b. It allows increased amounts of UV radiation to reach Earth's surface.
c. It increases crop yields.
d. It contaminates ground water.

Answer:

C.

Explanation:

Transition elements  like,  for example,  iron:

Fe2+  green colored in solution.

Fe3+  brown colored in solution.

Answer:

4.5 moles of lithium sulfate are produced.

Explanation:

Given data:

Number of moles of lead sulfate = 2.25 mol

Number of moles of lithium nitrate = 9.62 mol

Number of moles of lithium sulfate = ?

Solution:

Chemical equation:

Pb(SO₄)₂ + 4LiNO₃      →     Pb(NO₃)₄ + 2Li₂SO₄

Now we will compare the moles of lithium sulfate with lead sulfate and lithium nitrate.

                       Pb(SO₄)₂        :         Li₂SO₄

                            1                :             2

                          2.25           :          2/1×2.25 = 4.5 mol

                       LiNO₃            :             Li₂SO₄

                           4                :                2

                           9.62           :             2/4×9.62 = 4.81 mol

Pb(SO₄)₂  produces less number of moles of Li₂SO₄ thus it will act as limiting reactant and limit the yield of  Li₂SO₄.      

Answer: because helium molecules get bigger when they heat up, so if your balloons keep getting hotter, they will eventually pop.

Explanation:hope these gave u a clue and have a wonderful Christmas break ❄️

Explanation:

Because helium molecules grow bigger as they are heated up and eventually they popped out

Answer:

87.58 L of C₂H₂

Explanation:

We'll begin by calculating the number of mole in 250 g of CaC₂.

This can be obtained as follow:

Mass of CaC₂ = 250 g

Molar mass of CaC₂ = 40 + (12×2)

= 40 + 24

= 64 g/mol

Mole of CaC₂ =?

Mole = mass /Molar mass

Mole of CaC₂ = 250 / 64

Mole of CaC₂ = 3.91 moles

Next, the balanced equation for the reaction. This is given below:

CaC₂ + 2H₂O —> C₂H₂ + Ca(OH)₂

From the balanced equation above,

1 mole of CaC₂ reacted to produce 1 mole of C₂H₂.

Next, we shall determine the number of mole of C₂H₂ produced by the reaction of 250 g (i.e 3.91 moles) of CaC₂. This can be obtained as follow:

From the balanced equation above,

1 mole of CaC₂ reacted to produce 1 mole of C₂H₂.

Therefore, 3.91 moles of CaC₂ will also react to produce 3.91 moles of C₂H₂.

Finally, we shall determine the volume of C₂H₂ produced from the reaction. This can be obtained as follow:

Recall:

1 mole of any gas occupy 22.4 L at STP.

1 mole of C₂H₂ occupied 22.4 L at STP.

Therefore, 3.91 moles of C₂H₂ will occupy = 3.91 × 22.4 = 87.58 L

Thus, 87.58 L of C₂H₂ is produced from the reaction.

Answer:

The process of a solid becoming a liquid is called melting. (an older term that you may see sometimes is fusion). The opposite process, a liquid becoming a solid, is called solidification. For any pure substance, the temperature at which melting occurs—known as the melting point—is a characteristic of that substance.

Hope this helps, have a wonderful day/night, stay safe, happy holidays, and merry christmas!

Answer:

Acids are classified in the Bronsted Lowry acid-base theory as species, which losses hydrogen ions (H+, known as protons) in a chemical reaction (and are foundation species that accept hydrogen ions).

Answer:

Explanation:

number 12 is magnesium i think which is group lla which is B alkaline earths

Answer:

products

Explanation:

In chemistry, chemical reactions is the combination of two or more substances to yield other substances. The substances that react is called REACTANTS while the substances formed after the reaction is called PRODUCTS.

According to this question, a mixture of oxygen and hydrogen is ignited in a test tube as follows:

Hydrogen + Oxygen → Water + Energy

In this reaction, the substances being combined (usually found on the left side of the equation) are hydrogen and oxygen. Hence, oxygen and hydrogen are REACTANTS. Also, the substances produced as a result of the reaction is water (H2O). The PRODUCTS of the reaction is WATER.

Answer:

Soy isk polq ja uso??

Explanation:

Na uend qoaki uwsh.. aju qah!

The chemical formula of sodium hydroxide is NaOH, and its molar mass is 40.01 g/mol. It is the alkali salt of sodium, and its structure is shown below:

It is an ionic compound consisting of sodium cation (Na+) and hydroxide (OH-) anion.

Answer: D: bacteria

Explanation:

Explanation:

This is correct!

Ions that exist in both the reactant and product side of the equation are referred to as spectator ions. Overall, they do not partake in the reaction. If they are present on both sides of the equation, you can cancel them out.

An example is;

Na+(aq) + Cl​−​​(aq) + Ag​+(aq) + NO​3​−​​(aq) → Na​+​​(aq) + NO​3​−​​(aq) + AgCl(s)

The ions; Na+, NO​3​−​​(aq) would be cancelled out to give;

Cl​−​​(aq) + Ag​+(aq)  → AgCl(s)

Answer:

Here^

Explanation:

The matter starts heating, up as if it's ice , turns into a liquid.

Answer:

C

Explanation:

a hypothesis always comes first

Answer:

C

Explanation:

They form hypothesis first, then perform the experiment to test the hypothesis. After multiple experiments, they form a theory.

Thus C is correct

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Answer:

See explanation

Explanation:

The equation of the reaction is;

CH3COOCH3 + H2O -------> CH3COOH + CH3OH

Now recall that the rate of reaction refers to the rate of disappearance of reactants or the rate of appearance of products. We indicate that reactants disappear by a negative sign placed in front of the concentration term of reactants.

Rate = k -d[CH3COOCH3]/dt

Rate = k d[CH3COOH]/dt

Rate = k d[CH3OH]/dt

Note; i did not write the rate in terms of water because it is a solvent that is present in large excess. Its concentration does not change with time.

Answer:

The empirical formula is PbC₈H₂₀

Explanation:

To determine the empyrical formula, we need to determine the % of each element:

(38.43g  / 60 g ). 100 = 64.05 % of Lead

(17.83 g / 60 g) . 100 = 29.72 % of Carbon

(3.74 g / 60 g) . 100 = 6.23 % of H

Now we divide by the atomic mass:

64.05 / 207.2 = 0.309

29.72 / 12 = 2.48

6.23 / 1 = 6.23

We pick the lowest value and we divide again, with this number

0.309 / 0.309 = 1 Pb

2.48 / 0.309 = 8 C

6.23 / 0.309 = 20 H

PbC₈H₂₀

NaH is an ionic compound as shown below, and is made of sodium cations (Na+) and hydride anions (H-). It has the same octahedral crystal structure as NaCl, with each sodium ion surrounded by six hydride ions. The free hydride ions give this molecule its strong basic character. hope this helps

Answer:

halogens

Explanation:

Electronegativity increases as you move to the right and up the periodic table. Thus, halogens would have the greatest electronegativity.

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Answer:

Solid: calcium and potassium

Liquid: mercury and bromine

Gaseous: oxygen and fluorine

Explanation:

Matter exists in three different states namely: solid, gaseous and liquid. Elements that are found in nature are classified as matter. Since, these elements are grouped as matter, they can either be found as either solids, liquids or gases at normal temperature and pressure.

At normal temperature (20°C or 293K) and pressure (1 atm), the following elements are found to exists in the respective state of matter:

Solid: Calcium (Ca) and potassium (K)

Liquid: Mercury (Hg) and bromine (Br)

Gaseous: Oxygen (O) and fluorine (F)

Answer:

3000kg

Explanation:

Given parameters:

Speed = 20m/s

Kinetic energy  = 600000J

Unknown:

Mass  = ?

Solution:

Kinetic energy is the energy due to the motion of a body.

It is expressed as;

  K.E  = [tex]\frac{1}{2}[/tex] m v²  

m is the mass

v is the speed

  Now find m;

        600000 =  [tex]\frac{1}{2}[/tex]  x m x 20²

        600000 = 200m

         m  = 3000kg

Answer:

a) p waves travel slower then 5 waves

Answer:

A

Explanation:

As you add a bulky group to the end of a carbon chain the boiling point goes up on the molecule.

Answer:

sun

Explanation:

because all plants use energy from the sun to make food and grow

Answer:

The temperature finally increased from 20 °C to 38.7 °C

Explanation:

This a problem about calorimetry. Formula to solve it is:

Q = m . C . ΔT

Where ΔT is Final T° - Initial T°

m is the mass

and C, specific heat.

In this situation we are dissolving NaOH where 1 mol requires 44.4 kJ of heat. As we do not have 1 mol, we need to determine the heat that is released.

We convert the mass to moles

14.1 g . 1 mol / 40g = 0.3525 mol

We determine the heat

0.3525 mol . 44400 J/mol = 15651 Joules of heat.

Now we can replace data in the calorimetry formula:

15651 J = 200 g . 4.18 J/g°C (Final T° - 20°C)

15651 J / (200 g . 4.18 J/g°C) = Final T° - 20°C

18.7°C + 20°C = Final T° → 38.7°C

The percent  by volume of a solution : 19.23%

Given

50 ml of ethanol

210  ml of water

Required

The percent  by volume of a solution

Solution

Percent Volume (% v/v) : volume (ml) of solute/100 ml of solution ⇒ ratio of the volume of the solute to total volume of the solution

[tex]\tt \%solute(v/v)=\dfrac{solute~volume}{solution~volume}\times 100\%[/tex]

solute= Ethanol

solvent=water

Solution = solute+solvent

Total volume of the solution :

[tex]\tt =volume~of~Ethanol+solume~of~water\\\\=50~ml+210~ml\\\\=260~ml[/tex]

Percent by volume :

[tex]\tt \%volume=\dfrac{50}{260}\times 100\%\\\\\%volume=19.23\%[/tex]

Answer:

helium

Explanation:

By losing an electron, they look like the noble gas that immediately precedes them on the periodic table.

Answer:

d. naoh

Explanation:

Answer: They lose them :)

Explanation: