Which of the following is the correct chemical formula for Ca and F? CaF Ca2F CaF2

Answer:

New ideas would be created and tested

Explanation:

All old ideas would be discarded.

Scientific evidence would be weakened.

New ideas would be created and tested.

The limitations of science would be evident.

In science, old ideas are usually improved or modified and not entirely discarded. The old ideas form the basis for new ideas after extensive reviews. Differences in the interpretations made by scientists on any particular phenomenon give rooms for reviews. The reviews often generate new ideas or hypotheses and these can be tested using relevant experimental procedures according to the scientific method.

Hence, the correct answer would be that new ideas would be created and tested.

Answer:

Explanation:

given mass on earth =98 kg

gravitational pull on mars =3.711 m/s2

gravitational pull on venus =8.87 m/s2

weight of the body on mars =weight on earth/9.81 m/s2 *3.711 m/s2

W=98 kg*3.711 /9.81m/s2

W=37.07 kg

weight on the venus =weight on earth*8.87 m/s2 /9.81 m/s2

W= 98 kg*7.87 m/s2/9.81 m/s2

W=78.62 kg

Answer:

B.They do not react chemically

Explanation:

This is because all noble gases haves full outer shell therefore they don’t participate in bonding.They are referred to as inert which means unreactive.

Answer:

They do not react chemically

Explanation:

Explanation:

Hi there!!

you asked to multiply these all right,

you can simply multiply it ,

=3cm × 4 cm × 1cm

= 12cm^2×1cm (4×3=12)

= 12cm^3 (12×1=12)

Therefore, theanswer is 12 cm^3.

Hope it helps..

Answer:

Because they cannot be separated into more then one type of substance.

Explanation:

Answer:

Elements are made of only one kind of atom. The particles can be a single atom or a molecule made of only one kind of atom. There is no physical change that can separate elements into more than one kind of substance. This makes an element a pure substance.An element is made up of only one type of atom. An element cannot be broken down into a simpler form.

Explanation:

SOLID

Sodium hydroxide exists in the solid phase at room temperature. You would find it in the lab as hemispherical white solid pellets. The phase of a substance depends on temperature and pressure. As you heat a solid, it will melt and change to the liquid phase.

Answer:

(ii) Ethane and Heptadecane

Explanation:

The separation of all the species listed in the answer options for the question depends on the molar mass of each specie.

Ethane is a low molecular mass gas. It exists in the gaseous state at room temperature. However, heptadecane appears as a liquid because it has a greater relative molecular mass.

It is very easily to distinguish between the gas, ethane and the liquid heptadecane which is a high molecular mass alkane, hence the answer.

Answer:

solid

Explanation:

Answer:

d

Explanation:

Answer:

The answer is Neon

Answer:

neon

Explanation:

neon has a complete outer 2n shell

Answer: burning paper

Explanation:

The paper burns in air to form smoke and ash. which makes it a chemical change.

Answer:

The correct answer is 15.54 kJ per degree C.

Explanation:

The enthalpy change for one mole of a substance, which combines or burns with the oxygen under the standard conditions, that is, at 25 degree C and 1 bar pressure is known as the standard molar enthalpy of combustion. The amount of heat transferred can be calculated by using the formula, q = mcΔT -------------(i)

Here q is the amount of heat transferred, c is the specific heat, ΔT is the change in temperature, and m is the mass of the substance. As in case of bomb calorimeter, mass if considered constant, thus, for calorimeter the equation mentioned will become, q = cΔT ---- (ii)

The standard molar enthalpy of combustion for carbon is -393.5 kJ/mol, that is, -393.5 kJ per mole of heat is generated by burning one mole of carbon. The molecular mass of carbon is 12 gram per mole.  

Thus, the number of moles of carbon equivalent to 0.562 grams of carbon can be determined as,  

Number of moles of carbon = mass / molecular mas

= 0.562 grams / 12 gram per mole

= 0.047 mol

The heat generated by burning 0.562 grams or 0.047 mole will be,  

q = ΔH° × number of moles

= (-393.51 kJ/mol) × 0.047 mol

= -18.49 kJ, the negative sign shows that the heat is produced.  

To find heat capacity of calorimeter, put the value of q as -18.49 kJ, for ΔT as (27.93 °C - 26.74 °C) in the equation (ii)

18.49 kJ = c × (27.93 - 26.74)

c = 18.49 kJ/1.19 °C

c = 15.54 kJ/°C

Answer:

The three compounds are different compounds

Explanation:

The mass of Nitrogen that combines with 1 gram of Oxygen in  Compound A = 1.750 g

The mass of Nitrogen that combines with 1 gram of Oxygen in  Compound B  = 0.8750 g

The mass of Nitrogen that combines with 1 gram of Oxygen in  Compound C  = 0.4375 g

According to the law of multiple proportions, when atoms of two different elements react to form compounds, the masses of one of the elements that combines with a fixed mass of the other element are in small whole number ratios.

The ratio of the masses are;

Mass of Nitrogen in Compound B/(Mass of Nitrogen in Compound C =  0.8750/0.4375 = 2

Mass of Nitrogen in Compound A/(Mass of Nitrogen in Compound C =  1.750/0.4375= 4

Mass of Nitrogen in Compound A/(Mass of Nitrogen in Compound B =  1.750/0.8750= 2

Given that the masses of Nitrogen in the three compounds are in small whole number ratios, the three compounds, Compound A, Compound B, and Compound C are different compounds.

Answer:

Photometer

Explanation:

A photometer (photo comes from the Greek for light) measures the light coming from 140,000 stars in Kepler's stationary field of view. If a planet transits (passes in front of) any star the amount of light from the star is reduced enough so that the photometer senses it and relays the information back to the Kepler team.

Scientific instruments are tools used for researching the universe and natural sciences. A Photometer is sensitive enough to detect a planet transiting a star. Thus, option D is correct.

A Photometer is a device that converts light energy into electrical voltage by the photoelectric effect given by Einstein. It uses Quantum mechanics to convert the energy possessed by the photons and electrons. It follows Ohm's law to convert energy.

It is used to detect the planets transiting stars as they can detect the light energy as it uses the electromagnetic radiation of various wavelengths to convert them by the photodiode, resistor, and a multiplier.

Therefore, option D. a photometer is used to detect the planets in the universe transiting stars.

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Your question is incomplete, but most probably your full question was, What scientific instrument is sensitive enough to detect a planet transiting a star?

Answer:

New volume of chlorine gas (V2) = 179 ml (Approx)

Explanation:

Given:

Volume of chlorine gas (V1) = 193 ml

Temperature of chlorine gas (T1) = 21°C = 21 + 273 = 294 k

New temperature of chlorine gas (T2) = 0°C = 0 + 273 = 273 k

Find:

New volume of chlorine gas (V2) = ?

Computation:

Using charle's law

V1 / T1 = V2 / T2

193 / 294 = V2 / 273

V2 = 179.21

New volume of chlorine gas (V2) = 179 ml (Approx)

Answer:

D. A combustion reaction

Explanation:

Answer:

The pH of the solution following the addition of 0.075 moles of NaOH is 5.7.

Explanation:

The equation of the buffer solution is the following:

C₄H₇O₂H(aq) + H₂O(l) ⇄ C₄H₇O₂⁻(aq) + H₃O⁺(aq)     (1)    

The pH of the buffer solution can be found using the Henderson-Hasselbalch equation:

[tex] pH = pKa + log(\frac{[NaC_{4}H_{7}O_{2}]}{[C_{4}H_{8}O_{2}]}) [/tex]   (2)

The NaOH added will react with butanoic acid tot produce sodium butanoate:

C₄H₇O₂H(aq) + OH⁻(aq) ⇄ C₄H₇O₂⁻(aq) + H₂O(l)  (3)          

[tex] n_{C_{4}H_{7}O_{2}H}_{i} = C*V = 0.107 M*1.30 L = 0.139 moles [/tex]

[tex] n_{C_{4}H_{7}O_{2}^{-}} = 0.345 M*1.30 L = 0.449 moles [/tex]

[tex] n_{NaOH} = 0.075 moles [/tex]

[tex] n_{C_{4}H_{7}O_{2}H} = 0.139 moles - 0.075 moles = 0.064 moles [/tex]

[tex] n_{C_{4}H_{7}O_{2}^{-}} = 0.449 moles + 0.075 moles = 0.524 moles [/tex]

[tex]C_{C_{4}H_{7}O_{2}H} = \frac{0.064 moles}{1.30 L} = 0.049 M[/tex]

[tex] C_{C_{4}H_{7}O_{2}^{-}} = \frac{0.524 moles}{1.30 L} = 0.403 M [/tex]

Now, from equation (1) we have:

C₄H₇O₂H(aq) + H₂O(l) ⇄ C₄H₇O₂⁻(aq) + H₃O⁺(aq)

0.049 - x                           0.403 + x            x  

[tex] Ka = \frac{[C_{4}H_{7}O_{2}^{-}][H_{3}O^{+}]}{C_{4}H_{7}O_{2}H} [/tex]

[tex]1.52 \cdot 10^{-5} = \frac{(0.403 + x)x}{0.049 - x}[/tex]

[tex]1.52 \cdot 10^{-5}*(0.049 - x) - (0.403 + x)x = 0[/tex]

By solving the above equation for x we have:            

x = 1.85x10⁻⁶ = [H₃O⁺]

So, the concentration of butanoic acid and sodium butanoate is:

[tex][C_{4}H_{7}O_{2}^{-}] = 0.345 + 1.85 \cdot 10^{-6} = 0.345 M[/tex]

[tex][C_{4}H_{7}O_{2}H] = 0.049 - 1.85 \cdot 10^{-6} = 0.049 M[/tex]

Finally, from equation (2) we have:

[tex] pH = pKa + log(\frac{[NaC_{4}H_{7}O_{2}]}{[C_{4}H_{8}O_{2}]}) [/tex]

[tex]pH = -log(1.52 \cdot 10^{-5}) + log(\frac{0.345}{0.049}) = 5.7[/tex]

Therefore, the pH of the solution following the addition of 0.075 moles of NaOH is 5.7.

I hope it helps you!

Answer:

-A molecule is the smallesr part is compound whereas a compound is the combination of two or more atoms in a fixed proportion by wiehgt.

- A glass of water is an example of compound but a small portion of water can be called molecule.

There would be an increase in the concentration of carbonic acid - this is how an increase in carbon dioxide concentration influences the system.

In chemistry, a dynamic equilibrium lives once a reversible reaction occurs. Substances transition between the reactants and products at equal rates, indicating there is no net change. Reactants and products exist formed at such a rate that the concentration of neither changes. It is a precise example of a system in a steady state. After a time, a reversible reaction in a closed system can get what we call a dynamic equilibrium.

The correct answer is option D.

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Answer: In science, a hypothesis is a possible explanation for an observation, while a theory is an explanation that is supported by a large body of evidence.

Explanation: exact answer

Answer:

Below is the clarification of that same particular question.

Explanation:

For that kind of weak diprotic predictor, the standard economic statement can indeed be published as:

    ⇒  [tex]H_2In_(aq)\rightleftharpoons In^{2-} +2H^+[/tex]

Answer:

Yes, it is possible. Let us consider an example of two solutions, that is, solution A having 20 percent mass RbCl (rubidium chloride) and solution B is having 15 percent by mass NaCl or sodium chloride.  

It is found that solution A is having more concentration in comparison to solution B in terms of mass percent. The formula for mass percent is,  

% by mass = mass of solute/mass of solution * 100

Now the formula for molality is,  

Molality = weight of solute/molecular weight of solute * 1000/ weight of solvent in grams

Now molality of solution A is,  

m = 20/121 * 1000/80 (molecular weight of RbCl is 121 grams per mole)

m = 2.07

Now the molality of solution B is,  

m = 15/58.5 * 1000/85

m = 3.02

Therefore, in terms of molality, the solution B is having greater concentration (3.02) in comparison to solution A (2.07).

Answer:

oxygen is the chemical element with the atomic number is 8 and the symbol is o its known as called oxygen.

Explanation:

Oxygen is the most third element in the universe at they standard and temperature and pressure,and oxides most elements as other compounds.

Oxygen gas is the earth atmosphere is 21%, an oxygen is the half of the earth crust in form of oxide,oxygen is liquid and solid gas.

Oxygen atoms such as proteins and acids, fats the major organic compounds, oxygen as component of the water and carbon dioxide.

Oxygen has many characteristics :- properties and molecular structure:-

this  is a pressure and temperature  with molecular formula referred as oxygen,simply describe a double bond and molecular orbits.

Physical properties:- oxygen is highly substance and must be combustible materials, oxygen may also from using a liquid nitrogen coolant, molecular oxygen is the associated with the process of air glow.

Stellar origin :- all of the remaining to half lives to the majority of are less then milliseconds.

Occurrence:- oxygen is the process part of the element in the earth crust, free oxygen is also occurs in the world bodies.

Analysis :- analysis to the structure of vegetation and the carbon cycle on a global scale.

1.

Fe +52 - Fe253

SYNTHESIS REACTION

A synthesis reaction occurs when two or more reactants combine to form a single product.

2.

Pb(NO3)2 + K2CrO 4 PbCrO 4 +KNO3

DOUBLE REPLACEMENT

A double-replacement reaction exchanges the cations (or the anions) of two ionic compounds.

3.

H2 + N2 + NH3

SYNTHESIS REACTION

A synthesis reaction occurs when two or more reactants combine to form a single product.

4.

Fe + CuCl2 - FeCl2 + Cu

SINGLE REPLACEMENT

A single-displacement reaction, is a chemical reaction in which one element replaces an/other element in a compound.

Note. An element can only replace an element that it is higher than in the electrochemical series or an element that is less reactive than itself.

5.

KCIO3 -KCI + O2

DECOMPOSITION REACTION

A decomposition reaction is a reaction in which a compound breaks down into two or more simpler substances.

Most times this type of reaction requires an in put of energy.

It is usually an endothermic reaction as heat is mostly absorbed.

6.

Mg + HCI-H2 + MgCl2

SINGLE REPLACEMENT

A single-displacement reaction, is a chemical reaction in which one element replaces an/other element in a compound.

Note. An element can only replace an element that it is higher than in the electrochemical series or an element that is less reactive than itself.

7.

C3Hg + O2 CO2 + H2O

COMBUSTION REACTION

Combustion reaction is a high-temperature exothermic redox chemical reaction between a fuel (example propane C3H8) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products.( mostly C02)

It can also be referred to as burning.

Combustion reaction is one of the chemical characteristics of hydrocarbons.

8.

Zn + HCI - ZnCl2 + H2

SINGLE REPLACEMENT

A single-displacement reaction, is a chemical reaction in which one element replaces an/other element in a compound.

Note. An element can only replace an element that it is higher than in the electrochemical series or an element that is less reactive than itself.

9.

NH3-N2 + O2

DECOMPOSITION REACTION

A decomposition reaction is a reaction in which a compound breaks down into two or more simpler substances.

Most times this type of reaction requires an in put of energy.

It is usually an endothermic reaction as heat is mostly absorbed.

10.

AgNO3 + Cu Cu(NO3)2 + Ag

f70X

SINGLE REPLACEMENT

A single-displacement reaction, is a chemical reaction in which one element replaces an/other element in a compound.

Note. An element can only replace an element that it is higher than in the electrochemical series or an element that is less reactive than itself.

Answer:

1.29* 10^2

Explanation:

multiply them and then round

Answer:

%m/v =70%

Explanation:

El %m/v es una unidad de concentración que se define como cien veces la división entre la masa de una sustancia (En gramos) y el volumen total en el que esta sustancia se encuentra (en mL).

En el problema, debemos hallar la masa de etanol (Alcohol) y el volumen total de la solución.

Masa alcohol:

Ya te la dan en el problema: 105g

Volumen solución:

Volumen agua: 15mL

Volumen etanol: 105g × (1mL / 0.798g) = 131mL

Volumen Jabón líquido: 4.5g × (1mL / 1.5g) = 3mL

Volumen: 15mL + 131mL + 3mL

149mL

Así, el %m/v de alcohol en la solución es:

%m/v = (105g / 149mL) × 100

Answer:

The answer is D. Hydrochloric acid solution with a pH of 1.

Explanation:

I just took the same quiz

Hydrochloric acid solution with a pH of 1. Hence, option D is correct.

An acid is an electrolyte that hydrolyses in water to release hydrogen ions.

The lower the pH the greater the concentration of H+ ions. Hydrochloric acid with a pH of 1 is a strong acid and is highly ionised in solution.  It has the most H+ ions.

Hence, option D is correct.

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