Please help! I'm confused on a few of these, 100 points!

Calcium (Ca) is in group 2 and period 4 on the periodic table be because Calcium has 2 valence electrons and 4 electron shell. Thus, calcium is a metal like all other group 2 element.

The correct answer to the question is Option C. Calcium, like all group 2 elements, is reactive and a solid at room temperature.

Calcium is a group 2 element majorly because it has 2 valence electrons. It is also in period 4 because it has 4 electron shells.

Being a group 2 element, calcium is a solid at room temperature and also reactive. All elements in the group 2 are metals.

There are other elements in period 4 which are not solid. For example krypton is an element in period 4 and it is a gas and not reactive.

From the above information, we can conclude that the correct answer to the question is:

Option C. Calcium, like all group 2 elements, is reactive and a solid at room temperature.

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Answer:

I think it's A and D

Explanation:

I'm not sure if it's right

Answer:

The answer is B and D

Explanation:

trust fr

Answer:

4.22mL

Explanation:

V=m/d

v= 18.45g/4.37g/mL

Answer:

2.35 x 10²⁰ atoms Ga

Explanation:

After converting from mg to g, use the molar mass as the unit converter to convert to moles. Then using Avogadro's number, 6.022 x 10²³ convert from moles to atoms of Ga.

[tex]27.2mgGa*\frac{1g}{1000mg} *\frac{1 mol Ga}{69.72gGa} *\frac{6.022*10^2^3 atoms Ga}{1 molGa} = 2.349 * 10^2^0 atoms Ga[/tex]

Then round to 3 significant figures = 2.35 x 10²⁰ atoms Ga.

The number of atoms in 27.2 mg sample of Ga is 2.35 × 10²⁰ atoms

From the question, we are to calculate the number of atoms in a 27.2 mg sample of Ga.

First, we will determine the number of moles of Ga present

Using the formula,

[tex]Number\ of\ moles = \frac{Mass}{Molar\ mass} [/tex]

Mass = 27.2 mg = 0.0272 g

Molar mass = 69.72 g/mol

Then,

[tex]Number\ of\ moles \ of\ Ga = \frac{0.0272}{69.72} [/tex]

[tex]Number\ of\ moles \ of\ Ga = [/tex] 0.000390132 moles

Now, for the number of atoms present

From the formula

Number of atoms = Number of moles × Avogadro's constant

Then,

Number of Ga atoms = 0.000390132 × 6.022×10²³

Number of Ga atoms = 2.35 × 10²⁰ atoms

Hence, the number of atoms in 27.2 mg sample of Ga is 2.35 × 10²⁰ atoms

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Answer:

Explanation:

Iodine is the most flexible of the atoms in Group 17 of the periodic table. It can have more than 1 charge, especially when combined with oxygen. The answer that you are expected to give, I think is C. Iodine's dominant charge is - 1

The correct answer is Migrating farther into the sea

Explanation:

The Adálie penguins rely on ice sheets to obtain food as the krill they feed on is only found underside of the ice. This implies as the Antarctic sea ice melts Adálie penguins need to look for new places to find krill as if there are no ice sheets there are no krill for these penguins. Due to this, it is likely these penguins are forced to migrate or move farther into the sea to survive because it is likely in these zones there are ice sheets and therefore places where they can find krill. Despite this, this process might lead to a significant decline in the population of penguins due to the competence for food and the process of migration itself. Thus, the one that would help Adáline penguins to survive during the melting of Antarctic sea ice is migrating farther into the sea.

Have a nice day!   :)

The Adálie penguins feed on krill that live on the underside of ice sheets. Adálie penguins survive during the melting of Antarctic sea ice help migrating farther into the sea. Therefore, option A is correct.

The term migration is defined as the movement of either people or animals from one area to another.

The Adálie penguins rely on ice sheets for food because the krill they eat is only found on the underside of the ice. As a result, it is likely that these penguins are forced to migrate or move further into the sea to survive.

Regardless, this process may result in a significant decline in penguin population due to food competence and the migration process itself.Thus, the one that will assist Adáline penguins in surviving during the melting of Antarctic sea ice is migrating deeper into the sea.

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Your question is incomplete,most probably your question was

The Adálie penguins feed on krill that live on the underside of ice sheets. Which of the following would help Adálie penguins survive during the melting of Antarctic sea ice? Migrating farther into the sea Breeding during summer months Growing strong toe nails to grip ice Spending more time raising their young

Answer:

outer electrons

Explanation:

Answer:

Energy levels

Explanation:

Answer:

Mass = 23.232 g

Explanation:

Given data:

Mass of C₈H₁₈ = 7.58 g

Mass of CO₂ produced = ?

Solution:

Chemical equation:

2C₈H₁₈ + 25O₂      →     16CO₂ + 18H₂O

Number of moles of octane:

Number of  moles =  mass/molar mass

Number of moles = 7.58 g/ 114.23 g/mol

Number of moles = 0.066 mol

Now we will compare the moles of CO₂ with octane from balance chemical equation.

                  C₈H₁₈            :           CO₂

                       2              :              16

                 0.066             :           16/2×0.066 = 0.528

Mass of CO₂ produced:

Mass = number of moles × molar mass

Mass = 0.528 mol × 44 g/mol

Mass = 23.232 g

Answer:

Explanation:

NaNO₃  = Na⁺  + NO₃⁻¹

.497 M                 .497 M

moles of NO₃⁻¹ = .897 x .497 = .4458 moles

Ca( NO₃)₂  = Ca + 2 NO₃⁻¹

.341 M                    2 x .341 M = .682 M

moles of NO₃⁻¹ = .813 x .682 = .5544 moles

Total moles =  .4458 moles  +  .5544 moles

= 1.0002 moles

volume of solution = 897 + 813 = 1710 mL

= 1.710 L

concentration of nitrate ion = 1.0002 / 1.710 M

= .585 M

Answer:

ejeb094

Explanation:

nnb3neneie9eei rje

Answer:

Several extractions is more effective than a single extraction.

Explanation:

When extraction is carried out multiple times, for instance, in this case, the extraction was carried out with three portions of the solvent rather than with just a single portion of the solvent, the amount of material left in the residue will be lower, because the extraction is more complete.

Several extractions with smaller volumes of solvent are more effective than a single extraction with a large volume of solvent.

Complete Question

You are given a solution containing a pair of enantiomers (A and B). Careful measurements show that the solution contains 98% A and 2% B. What is the enantiomeric excess?

Answer:

The value is  [tex]k  = 96 %[/tex]

Explanation:

From the question we are told that

   The  percentage of  enantiomer A is  A =  98%

    The  percentage of  enantiomer B is  B =  2%

Generally the enantiomeric excess is mathematically represented as

      [tex]k  =  \frac{A -B}{A+B}  *  100[/tex]

=>   [tex]k  =  \frac{98 -2}{98+2}  *  100[/tex]

=>   [tex]k  = 96 %[/tex]

C – 19,9%, H – 2,2%, N – 11,6%, O – x%

[tex]M=120\frac{g}{mol}[/tex]

1 percentage

The entire molecule is 100% and all the components of the compound add up to 100%.

100% - 19,9% - 2,5% - 11,6% = 66,1%

The compound contains 66,1% oxygen.

2 molar masses

[tex]M_{C}=12,01\frac{g}{mol}[/tex]

[tex]M_{H}=1,008\frac{g}{mol}[/tex]

[tex]M_{O}=15,999\frac{g}{mol}[/tex]

[tex]M_{N}=14,007\frac{g}{mol}[/tex]

3 masses

The compound has a molar mass of 120g/mol. So one molecule weighs 120 g. To find out how much the percentage of a component weighs, you have to calculate it using the molar mass.

carbon

19,8% of 120g

[tex]m=120g*0,198\\m=23,76g[/tex]

One molecule contains 23,76g of carbon.

hydrogen

2,5% of 120g

[tex]m=120g*0,025\\m=3g[/tex]

One molecule contains 3g of hydrogen.

oxygen

66,1% of 120g

[tex]m=120g*0,661\\m=79,32g[/tex]

One molecule contains 79,32g of oxygen.

nitrogen

11,6% of 120g

[tex]m=120g*0,0,116\\m=13,92g[/tex]

One molecule contains 13,92g of nitrogen.

4 amount of substance

carbon

[tex]n=\frac{23,76g}{12,01\frac{g}{mol} }\\n=1,98mol[/tex]

The compound contains about 2 moles of carbon.

hydrogen

[tex]n=\frac{3g}{1\frac{g}{mol} }\\n=3mol[/tex]

The compound contains about 3 moles of hydrogen.

oxygen

[tex]n=\frac{79,32g}{15,999\frac{g}{mol} }\\n=4,96mol[/tex]

The compound contains about 5 moles of oxygen.

nitrogen

[tex]n=\frac{13,92g}{14,007\frac{g}{mol} }\\n=0,99mol[/tex]

The compound contains about 1 moles of nitrogen.

5. molecular formula

The formula results from the ratio of the amounts of substance.

[tex]n_{C} :n_{H} :n_{O} :n_{N} =2:3:5:1\\C_{2}H_{3}NO_{5}[/tex]

The molecular formula of the given compound is C₂H₃NO₅, and percent composition of oxygen in it is 66.1%.

Mass of any composition of any compound will be calculated by using the below formula as:

Mass of component = (% composition)×(mass of compound) / 100

Given mass of compound = 120g/mol

Total composition of compound (100%) = Percent composition of all components

% composition of oxygen = 100 - (19.8 + 2.50 + 11.6) = 66.1%

Moles will be calculated as:

n = W/M, where

W = given mass

M = molar mass

Mass of Carbon component = (0.198)(120g) = 23.76g

Moles of Carbon atom = 23.76g / 12.01g/mol = 1.98mol = 2 moles

Mass of Nitrogen component = (0.116)(120g) = 13.92g

Moles of Nitrogen atom = 13.92g / 14.007g/mol = 0.99mol = 1 moles

Mass of Oxygen component = (0.661)(120g) = 79.32g

Moles of Oxygen atom = 79.32g / 15.99g/mol = 4.96mol = 5 moles

Mass of Hydrogen component = (0.025)(120g) = 3g

Moles of Hydrogen atom = 3g / 1g/mol = 3 moles

So, the molecular formula of the compound on the basis of moles of given entities is C₂H₃NO₅.

Hence required molecular formula is C₂H₃NO₅.

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Answer:

5Ns

momentum= mass *velocity

=1*5

=5Ns

Answer:

2,2,3- trimethylhexane because it has more carbon atoms than pentane.

Explanation:

Hello.

In this case, since the physical properties of organic compounds are intensified as the number of carbon atoms start increasing on it, the larger the amount of carbon atom, the higher the boiling point since more energy is required to allow the liquid-phase molecules to transcend to the vapor-phase.

In such a way, since pentane has five carbon atoms and 2,2,3- trimethylhexane has nine carbon atoms, 2,2,3- trimethylhexane has the highest boiling point.

Best regards.

Answer:

Explanation:

The new volume can be found by using the formula for Boyle's law which is

[tex]P_1V_1 = P_2V_2[/tex]

where

P1 is the initial pressure

P2 is the final pressure

V1 is the initial volume

V2 is the final volume

Since we are finding the new volume

[tex]V_2 = \frac{P_1V_1}{P_2} \\[/tex]

We have

[tex]V_2 = \frac{300 \times 2}{7} = \frac{600}{7} \\ = 85.714285...[/tex]

We have the final answer as

Hope this helps you

Answer:

b. No

Explanation:

The question above is related to "The Law of Conservation of Mass." This law states that mass is neither created nor can it be destroyed. Even if a particular matter will be mixed with another substance or it undergoes chemical reaction, the mass of the matter will remain the same. Even with a change in phase, the mass of the matter will remain the same.

Answer:

CHO

Explanation:

Carbon = 41%,  Hydrogen = 4.58%, oxygen = 54.6%

Step 1:

Divide through by their respective relative atomic masses

41/ 12,         4.58/1,         54.6/16

3.41              4.58            3.41

Step 2:

Divide by the lowest ratio:

3.41/3.41,      4.58/3.41,     3.41/3.41

1,                    1,                  1

Hence the empirical formula is CHO

Answer:

The empirical formula of X is C3H4O3.

Explanation:

Answer:

it is Calcium (Ca)

4th period, 2nd group, 2 valence electrons

Answer:

A) enthalpy of reaction

Explanation:

The region C signifies the enthalpy of reaction.

This diagram is the energy profile of an endothermic reaction. In such reaction, heat is absorbed from the surrounding. At the end of the reaction, the heat of product is lesser than that of the reactants.

it is indeed A) enthalpy of reaction

Answer:

the second answer its science behind it

Answer:

b

Explanation:

Answer:

a beaker

Explanation:

Answer:

Exothermic

Explanation:

Nuclear fission means splitting, so there is a lot of energy being released.

Answer:

+0.02 V

Explanation:

For the reaction to be spontaneous, iron must be the cathode and Mercury the anode

Given that the standard cell potential is obtained from;

E°=E° cathode - E° anode

Since;

E° cathode = -0.77V

E° anode = 0.79 V

E°cell = -0.77 -(-0.79)

E°cell = +0.02 V

Answer:

PH = 4.0

Explanation:

We are given;

Ka1 = 8.9 × 10^(-8)

Ka2 = 1.0 × 10^(-19)

From the 2 values of K given above, we can see that Ka2 is far smaller than Ka1.

Thus, Positive hydrogen ion (H+) will be majorly formed from first dissociation which is Ka1.

Now, the breakdown of the H2S solution is;

H2S⇌[H+] + [HS−]

Thus;

Ka1 = [[H+] × [HS2^(-)]]/(H2S)

HS2^(-) also has a positive hydrogen ion.

Thus, we can rewrite as;

Ka1 = [[H+] × [H+]]/(H2S)

Ka1 = (H+)²/(H2S)

Concentration of H2S is given as 0.1M. Thus;

8.9 × 10^(-8) = (H+)²/0.1

(H+)² = 0.1 × 8.9 × 10^(-8)

(H+) = √(0.1 × 8.9 × 10^(-8))

(H+) = 0.00009433981

Now, PH is gotten from;

PH = -log (H+)

Thus;

PH = -log 0.00009433981

PH ≈ 4.0

Answer:

polar bonds are caused by different kind of atoms, because almost every atoms have different powers to attract electrons.

the answer will be the two same atoms, F2