20 POINTS PLEASE ANSWER ASAP!!!!

Why is calcium (Ca) in group 2, period 4 on the periodic table?

A Calcium, like all group 2 elements, is nonreactive and a gas at room temperature.

B Calcium, like all period 4 elements, is nonreactive and a gas at room temperature,

C Calcium, like all group 2 elements, is reactive and a solid at room temperature.
D. Calcium, like all period 4 elements, is reactive and a solid at room temperature.​

Answer:

the difference is tyat eruptions of less gassy and more gassy is that the less gassy doesnt retain as much gas as the more gassy one and thus the eruption of the less gassy is less damage to the more gassy

Answer:

b. gelatin

Explanation:

a homogeneous noncrystalline consisting of large molecules or ultramicroscopic particles of one substance.

Answer:

7.030682 kg

hope it helps!

Answer:

7.030682

Explanation:

Answer:

A gamma ray is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nuclei. It consists of the shortest wavelength electromagnetic waves and gives off the highest photon energy. The energy spectrum of gamma rays can be used to identify the decaying radionuclides using gamma spectroscopy.

Explanation:

Answer:

c

Explanation:

Answer:

8.69 is the pH at the equivalence point

Explanation:

Formic acid, HCHO₂, reacts with NaOH as follows:

HCHO₂ + NaOH → NaCHO₂ + H₂O.

At the equivalence point you will have in the reaction just NaCHO₂ and H₂O. The concentration of NaCHO₂ will be:

Moles: 0.0278L * 0.797mol/L = 0.02216moles

To reach the equivalence point it is necessary to add:

0.02216mol * (1L / 0.928mol) = 0.0239L

Total volume in the equivalence point:

0.0278L + 0.0239L = 0.0517L

Concentration: 0.02216moles / 0.0517L = 0.429M

The equilibrium of NaCHO₂, CHO₂⁻, in water is:

CHO₂⁻(aq) + H₂O(l) ⇄ OH⁻(aq) + HCHO₂(aq)

Where Kb, 5.56x10⁻¹¹ is defined as:

5.56x10⁻¹¹ = [OH⁻] [HCHO₂] / [CHO₂⁻]

In the equilibrium, it is produced X OH⁻ and HCHO₂, and as concentration of NaCHO₂ is 0.429M:

5.56x10⁻¹¹ = [X] [X] / [0.429M]

2.383x10⁻¹¹ = X²

4.88x10⁻⁶ = X = [OH⁻]

As pOH = -log [OH⁻]

pOH = 5.31

And pH = 14 - pH

pH = 8.69 is the pH at the equivalence point

Answer:

The dolphin's fast cruising speed (a travelling speed they can maintain for quite a while) is about 3-3.5 m/s (6-7 knots, 11-12.5 km/hr)

Explanation:

so 37 kilometers

Answer:

A) 0.831 M

B) 1.07 m

C) 26.2%

D) 0.0189

Explanation:

A) First we convert the mass of Pb(NO₃)₂ to moles:

Then we divide it by the total volume (1.00 L) to calculate the molarity:

B) We convert the grams of water to kilograms:

Then we divide the Pb(NO₃)₂ by the kilograms of water:

C) We divide the mass of Pb(NO₃)₂ by the total mass of the solution:

D) We calculate the moles of water:

Then we divide the Pb(NO₃)₂ moles by the total number of moles:

Answer:

Option C. K⁺(aq) and SO₄²¯(aq)

Explanation:

We'll begin by writing the ionic equation between H₂SO₄ and KOH.

This is illustrated below:

In solution, H₂SO₄ and KOH will dissociate as follow

H₂SO₄ (aq) —> 2H⁺ (aq) + SO₄²¯ (aq)

KOH (aq) —> K⁺ (aq) + OH¯ (aq)

Thus, aqueous H₂SO₄ and KOH will react as follow:

H₂SO₄ (aq) + 2KOH (aq) —> K₂SO₄ (aq) + 2H₂O (l)

Ionically:

2H⁺(aq) + SO₄²¯(aq) + 2K⁺(aq) + 2OH¯(aq) —> 2K⁺(aq) + SO₄²¯(aq) + 2H₂O (l)

The spectator ions are those ions that appear on both sides of the equation.

From the above ionic equation, the spectator ions are:

K⁺(aq) and SO₄²¯(aq)

Answer:

breathe,eat, and drink i guess

Answer:

C) an increase in rate of reaction because reactant molecules collide with greater energy

Explanation:

Temperature is one of the factors that affect the rate of a reaction. The rate of a reaction increases with an increase in temperature and vice versa. When the temperature of a reaction increases, the kinetic energy of the reactant molecules increases causing them to react at a faster rate.

The reactant molecules respond to an increase in temperature by colliding at a faster rate due to an increased kinetic energy between the reactant molecules.

Answer:

Volume of dry gas at STP = 0.432 liters or 432 ml

Explanation:

Given:

Pressure (P) = 740 mmHg - 24 mmHg = 716 mmHg

Temperature (t) = 25 degrees C + 273 K = 298 K

500 ml = 0.5 l

Find:

Volume of dry gas at STP

Computation:

[P1][V1] / T1 = [P2][V2] / T2

[716][0.5] / 298 K = [760][ x Liters] / 273 K

x = 0.432 Liters

Volume of dry gas at STP = 0.432 liters or 432 ml

Answer:

74.3kJ are transeferred

Explanation:

In the bomb calorimeter, the burning of C₈H₁₈ is producing heat that is been absorbed for the calorimeter and the water.

Heat absorbed calorimeter:

837J/°C * (33.8°C-15.0°C) = 15735.6J

Heat absorbed water:

C*m*ΔT

C specific heat of water (4.184J/g°C), m is mass of water (745g), and ΔT change in temperature (33.8°C - 15°C = 18.8°C)

4.184J/g°C*745g*18.8°C = 58601.1J

Heat released by the reaction:

15735.6J + 58601.1J = 74336.7J

Answer:

The plant uses carbon dioxide and water to make an entirely new chemical hence chemical change.

Explanation:

Plants create their own 'food', they turn carbon dioxide water and sunlight to create starch and glucose..

Answer:

The properties of carbon dioxide and oxygen are different.

Explanation:

im taking the exam right now and Im pretty sure it's D The properties of carbon dioxide and oxygen are different.

Answer:

1.9 × 10⁻³ M

Explanation:

Step 1: Write the acid ionization of benzoic acid

C₆H₅COOH(aq) + H₂O(l) ⇄ C₆H₅COO⁻(aq) + H₃O⁺(aq)

Step 2: Calculate the acid ionization constant (Ka) of benzoic acid

The pKa of benzoic acid is 4.20

pKa = -log Ka

Ka = antilog -pKa = antilog -4.20 = 6.31 × 10⁻⁵

Step 3: Calculate the equilibrium concentration of the hydronium ion

Considering that the initial concentration of the benzoic acid is Ca = 0.056 M, we can calculate the equilibrium concentration of the hydronium ion using the following expression.

[H₃O⁺] = √(Ca × Ka) = √(0.056 × 6.31 × 10⁻⁵) = 1.9 × 10⁻³ M

Answer:

I think it's C.90º

Explanation:

Answer:

180o

Explanation:

It is 180 degrees because the central atom is the atom in the middle of two electrons. Think about it like a straight line, a straight line is equal to 180 degrees. One electron connected to the central atom will be 90 degrees and if there's another electron, it will be 180 degrees.

Hope this helps:)

Answer:

0.31 mol

Explanation:

Answer:

outer electrons

Explanation:

Answer:

Energy levels

Explanation:

Complete Question

Sodium carbonate, Na2CO3(s), can be prepared by heating sodium bicarbonate, NaHCO3(s).

2NaHCO3(s) ------> Na2CO3(s) + CO2(g) + H2O(g) Kp = 0.23 at 100oC

If a sample of NaHCO3 is placed in an evacuated flask and allowed to achieve equilibrium at 100oC, what will the total gas pressure be?

Answer:

The value is  [tex]P_T  = 0.959 \  atm [/tex]

Explanation:

From the question we are told that

   The equation is  

[tex]2NaHCO_3_{(s)} \rightarrow  Na_2CO_3_{(s)} + CO2_{(g)} + H2O_{(g)}[/tex]

Generally the equilibrium partial pressure is mathematically represented as

    [tex]K_p =  P_{CO_2} + P_{H_2O}[/tex]

Here  

   [tex] P_{CO_2} \ and  \  P_{H_2O}[/tex] are partial  pressures of  [tex] CO_2 \ and  \ H_2O [/tex] gases

Note: when writing the formula for equilibrium partial pressure we consider only the gas in the reaction

Let assume that    

    [tex]P_{CO_2} =  a[/tex]

Generally  [tex]P_{CO_2} = P_{H_2O}[/tex] since they are both products of the reaction

  So  

       [tex]K_p =  a^2 [/tex]

From the question we are told that [tex]K_p =  0.23 [/tex]

So  

     [tex] 0.23=  a^2 [/tex]

=>  [tex] a = \sqrt{0.23} [/tex]

=>  [tex] a = \sqrt{0.23} [/tex]

=>  [tex] a = 0.4796  \ atm [/tex]

So

     [tex]P_{CO_2} =  0.4796  \ atm[/tex]

and

      [tex]P_{H_2O} =  0.4796  \ atm [/tex]

So the total pressure is

      [tex]P_T  =  0.4796  +  0.4796[/tex]

=>   [tex]P_T  = 0.959 \  atm [/tex]

Answer:

The solvent

Explanation:

After the solid is recoverd by decanting the liquid, some solvent particles may still adhere to the solid.

In order to remove the solvent that may have adhered to the solid completely , the solid is washed before it is now dried.

In order to remove the remaining liquid present the solid material.

We are washing the solid in order to remove the liquid particles that is attached to the solid material with the help of water. Water is a universal solvent that dissolve large number of solutes in it.

Water removes the liquid from the solid by attaching with that liquid or dissolving in it so that's why we use water for washing a solid in order to remove the impurities from the solid material in which it is placed.

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Answer:

See explanation

Explanation:

One basic thing that we must keep in mind is that A and B are both dienes.

The NMR spectrum and absorption maxima of A and B indicates that A may be a conjugated diene while B may be an isolated diene.

Remember that conjugated dienes shift the absorption maxima to longer wavelengths due to π - π* transition.

The two structures attached may suffice for compounds A and B

Answer:

the second on is, Changing the sequence of nucleotides in the DNA molecule can change the amino acids in the final protein, leading to protein malfunction. If insulin does not function correctly, it might be unable to bind to another protein (insulin receptor).

the first one is, These three polysaccharides differ in their glycosidic linkages and their functions too. Starting from the cellulose which is the monomer of beta glucose and is found in plant cell wall only. While Starch and Glycogen act as the carbohydrate reserve in plants and animals respectively. Though their chains have slight differences at the branching point, which is described below.

Explanation:

hope it helps

Answer:

c = π / R × T

Explanation:

The osmotic pressure exerted by a solution is equal to the molarity multiplied by the absolute temperature and the gas constant  R .  Suppose the osmotic pressure of a certain solution is measured to be  22 atm  at an absolute temperature of  353 K.  Write an equation that will let you calculate the molarity  c  of this solution. Your equation should contain only symbols. Be sure you define each symbol other than  R.

Step 1: Given data and definition of the symbols

Step 2: Write an equation that will let you calculate the molarity of this solution, in terms of symbols

The osmotic pressure is a colligative property that can be calculated using the following expression.

π = c × R × T

We can rearrange this expression to calculate the molarity of the solution.

c = π / R × T

Answer:

Atomic radii vary in a predictable way across the periodic table. As can be seen in the figures below, the atomic radius increases from top to bottom in a group, and decreases from left to right across a period. Thus, helium is the smallest element, and francium is the largest.

Explanation:

Answer:

To get the number of atoms in this sample, we first need the number of moles of lead in 11.3 grams

Number of moles of Lead:

Molar mass of lead = 207 grams / mol

Number of moles  = given mass / molar mass

Number of moles = 11.3 / 207

Number of moles = 0.05 moles

Number of atoms of lead in 11.3 gram sample:

Number of atoms = Number of moles * avogadro's number

Number of atoms = 0.05 * 6.022 * 10²³

Number of atoms = 5 * 10⁻² * 10²³ * 6.022

Number of atoms = 30.11 * 10²¹

11.3 g block of lead contains 3.29×10²² atoms

From Avogadro's hypothesis, we understood that 1 mole of any substance contains 6.022×10²³ atoms. Thus,

1 mole of lead = 6.022×10²³ atoms

Recall:

1 mole of lead = 207 g

Thus,

With the above information in mind, we can obtain the number of atoms in 11.3 g block of lead as illustrated below:

207 g of lead = 6.022×10²³ atoms

Therefore,

11.3 g of lead = (11.3 × 6.022×10²³) / 207

Thus, 11.3 g block of lead contains 3.29×10²² atoms

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Answer:

Exothermic

Explanation:

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

Answer:

its b  

B. 4

Explanation: