Which of these statements are true? Select all that apply. The Delta. Hf for Br2(I) is 0 kJ/mol. The Delta. Hf for He(I) is 0 kJ/mol. The Delta. Hf for Hg(I) is 0 kJ/mol. The Delta. Hf for Cl2(g) is 0 kJ/mol. The Delta. Hf for N2(I) is 0 kJ/mol.

Answer:

Fluorine is identified as the most reactive nonmetal and the most electro-negative element in the periodic table, making it the strongest oxidizing agent. Caesium is the most reactive metal in the periodic table, so much that working with this metal often ends in explosions!

Hydrogen is a very reactive gas, and the alkali metals are even more reactive. In fact, they are the most reactive metals and, along with the elements in group 17, are the most reactive of all elements.

Hope that helps.

Answer:

1.3 is the value with the lowest sig figs in your question. So we have 2 sig figs.

4568/1.3 = 3513.84615

Now let's change the answer in sig figs.

We know that trailing zeros don't actually count as part of sig figs.

So we can round the answer to 3500, having the 2 sig figs (3 and 5) while the trailing zeros don't count.

Final answer = 3500

Answer:

HF + LiOH = LiF + H2O.

Explanation:

Hydofluoric acid is a weak acid the solution would be slightly basic due to the following equilibrium (condition in the course of a reversible chemical reaction in which no net change in the amounts of reactants and products occurs.)

Hope that helps. x

We are given –

Here–

[tex]\qquad[/tex][tex] \pink{\bf \longrightarrow Initial\: velocity = 100 \:km/hr}[/tex]

[tex]\qquad[/tex][tex] \sf \longrightarrow Initial\: velocity = \dfrac{ 100 \times 1000}{3600} \:m/s[/tex]

[tex]\qquad[/tex][tex]\pink{ \bf \longrightarrow Initial\: velocity = 27.78\: m/s} [/tex]

Now –

[tex]\qquad[/tex]____________________________

[tex]\qquad[/tex][tex] \purple{\bf \longrightarrow Acceleration = \dfrac{Final\: Velocity -Initial \:Velocity }{Time}}[/tex]

[tex]\qquad[/tex][tex] \purple{\bf \longrightarrow Acceleration = \dfrac{v -u}{t}}[/tex]

[tex]\qquad[/tex][tex] \sf \longrightarrow Acceleration = \dfrac{(0- 27.78)}{1800}[/tex]

[tex]\qquad[/tex][tex] \sf \longrightarrow Acceleration =\cancel{ \dfrac{- 27.78}{1800}}[/tex]

[tex]\qquad[/tex][tex] \purple{\bf \longrightarrow Acceleration = -0.015 \: m/s^2} [/tex]

[tex]\qquad[/tex]_______________________________

Explanation:

and then name of the other product will be sodium sulphate

Answer:

Thomson  placed two magnets on either side of the tube, and observed that this magnetic field also deflected the cathode ray. The results of these experiments helped Thomson determine the mass-to-charge ratio of the cathode ray particles, which led to a fascinating discovery, minus the mass of each particle was much, much smaller than that of any known atom. Thomson repeated his experiments using different metals as electrode materials, and found that the properties of the cathode ray remained constant no matter what cathode material they originated from. From this evidence, Thomson made the following conclusions:

The cathode ray is composed of negatively-charged particles.

The particles must exist as part of the atom, since the mass of each particle is only ~1/2000 the mass of a hydrogen atom.

These subatomic particles can be found within atoms of all elements.

While controversial at first, Thomson's discoveries were gradually accepted by scientists. Eventually, his cathode ray particles were given a more familiar name: electrons. The discovery of the electron disproved the part of Dalton's atomic theory that assumed atoms were indivisible. In order to account for the existence of the electrons, an entirely new atomic model was needed.

Explanation:

Answer:

numbers of molecules = 3×6.023×10-23

Answer:

because it does not cost much and can be found easily.  due to their low resistance and excellent conductivity.

Explanation:

Answer:28.01 grams

Explanation:

Answer:

1.35 g

Explanation:

water is h2o, so the molar mass is 1.01x2+16.00=18.02. divide 4.5 x 10^22 by 6.022 x 10^23 to get 7.5 x 10^-2 (2 sig figs). 18.02 x 7.5 x 10^-2 is 1.35 g

The 10 karat of gold formed by melting gold with other metals is described as homogeneous mixture.

A pure substance is a substance that is made up of only one kind of particle. This type of substance consist of only one element.

A heterogeneous substance is a type of substance that is made up two or more substances existing in different phases.

A homogeneous substance is a type of substance that is made up of two or more substances evenly mixed. This type of substance exist only in one phase.

Thus, the 10 karat of gold formed by melting gold with other metals is described as homogeneous mixture.

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Answer:

homogeneous mixture

Explanation:

Answer:

he introduced triads of similar chemical properties in periodic table.

Explanation:

Answer:

A

Explanation:

is the best answer...........

Answer:

Neutralization occurs when a strong acid and a strong base come together in a chemical reaction to form water and salt.

Explanation:

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Answer:

Explanation:

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The mass of water is equal to 2.48 × 10⁷ g, needs the energy of 7.14 ×10¹⁰ J to heat and boil.

The specific heat capacity can be demonstrated as the quantity of energy needed to increase the temperature by one-degree Celcius in one unit of substance.

The temperature will be changed whenever there is a loss or absorption of energy by any substance.

Q = mCΔT

Therefore, there is a direct relationship between the mass of water and the amount of energy.

m ∝ q

[tex]{\displaystyle {\frac{m_1}{m_2} =\frac{q_1}{q_2}[/tex]

[tex]{\displaystyle {m_2} =\frac{q_2}{q_1} \times m_1[/tex]

Given, the energy required to heat mass(m₂) of water, q₂ = 7.14 ×10¹⁰ J

The energy to heat 1 gram of water, q₁ = 2870 J

[tex]{\displaystyle {m_2} =\frac{7.14\times 10^{14}}{2870} \times 1[/tex]

m₂ = 2.48 × 10⁷ g

Therefore, the mass of water is equal to  2.48 × 10⁷ g.

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#SPJ2

Explanation:

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[tex]\rule{2000pt}{1000000pt}[/tex]

mamama

Answer: Ammonia, an alkaline chemical, is used to raise the pH level (it's levels of acidity) of our hair during the colouring process. This then lifts the cuticles of the hair fibre and allows the colour to be deposited onto the cortex (the inner part of the hair protected by the cuticles). In hair coloring products, ammonium hydroxide is used to support the lightening action of hydrogen peroxide and to prepare hair to accept color pigments. Alkaline properties of ammonia raise the cuticle and allow peroxide and dye molecules to penetrate the hair shaft. (creds to the internet)

Explanation: Hope this helps! :D

Answer:

D

Explanation:

Given that the molar mass of NaCl is 58.44 g/mol, we want to determine the molarity of a solution that contains 87.75 g of NaCl in 500. mL of solution.

Recall that molarity is given by:

[tex]\displaystyle \text{M} = \frac{\text{ mols solute}}{\text{ liters soln.}}[/tex]

Therefore, we can convert the amount of NaCl in the solution to moles of NaCl and the volume from milliliters to liters:

[tex]\displaystyle \begin{aligned} \text{M} & = \frac{(87.75 \text{ g NaCl})}{(500. \text{ mL soln.})} \cdot \frac{1 \text{ mol NaCl}}{58.44 \text{ g NaCl}} \cdot \frac{1000 \text{ mL soln.}}{1 \text{ L soln.}} \\ \\ & = 3.00\text{ } \frac{\text{mol NaCl}}{\text{ L soln.}} \\ \\ & = 3.00 \text{ M} \end{aligned}[/tex]

Hence, our answer is D.

Answer:

13.8 moles

Explanation:

You know that in a mole you have 6.022x10²³ something in this case of molecules. By knowing that by each mole you have 6.022x10²³ molecules, then you can establish the factor of conversion:

8.32x10²⁴molec of CO2 x 1 mol/6.022x10²³ molec of CO2

You divide 8.32x10²⁴/6.022x10²³ and you get 13.81 moles.

Answer:

46.....................

The density of the gas is obtained as  0.55 g/L.

We can find the density of the gas using the relation;

PM = dRT

P = pressure of the gas

M = molar mass of the gas

d = density of the gas

R = gas constant

T = temperature

Now;

P = 29.9 kPa

R = 8.314 L·kPa mol·K.

T =  147°C + 273 = 420 K

d = ?

M = 64 g/mol

Substituting values;

d = PM/RT

d =  29.9 kPa ×  64 g/mol/ 8.314 L·kPa mol-1K-1 420 K

d = 1913.6/3491.88

d = 0.55 g/L

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Answer:

706 L

Explanation:

P1V1 = P2 V2 3 atm 250.0 mL = 1 atm X

T1 T2 290 K 273 K

706 mL = X

The process of grinding is a physical change that takes place in the mouth during digestion.

Grinding is one of the processes that occur during the digestion of food molecules into simpler substances.

Grinding of food molecules occurs in the mouth with the aid of the teeth, which is used to chew.

However, the process of grinding is a physical change because it does not result into the formation of new substances or change the chemical constituents of the food.

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Answer:

About 0.53 g of carbon dioxide needs to be added.

Explanation:

Recall the ideal gas law:

[tex]\displaystyle PV = n RT[/tex]

To determine the amount of carbon dioxide we need, we need to solve for n:

[tex]\displaystyle n = \frac{PV}{RT}[/tex]

Recall that P, V, and T are in atm, L, and K, respectively. R is the universal gas constant.

Convert all values into the correct units:

Volume:

[tex]\displaystyle 250\text{ mL } \cdot \frac{1 \text{ L}}{1000 \text{ mL}} = 0.25 \text{ L}[/tex]

Temperature:

[tex]\displaystyle \begin{aligned} K & =( ^\circ C) + 273.15 \\ \\ & = (-24) + (273.15) \\ \\ & = 249 \text{ K}\end{aligned}[/tex]

And pressure:

[tex]\displaystyle 95 \text{ kPa} \cdot \frac{1.00 \text{ atm}}{101.3 \text{ kPa}} = 0.94 \text{ atm}[/tex]

Substitute and evaluate:

[tex]\displaystyle\begin{aligned} n & = \frac{\left(0.94 \text{ atm}\right)\left(0.25 \text{ L}\right)}{\left(\dfrac{0.08206 \text{ L-atm}}{\text{mol-K}}\right)\left(249\text{ K}\right)} \\ \\ & = 0.012 \text{ mol CO$_2$}\end{aligned}[/tex]

Convert moles to grams:

[tex]\displaystyle 0.012 \text{ mol CO$_2$} \cdot \frac{44.01 \text{ g CO$_2$}}{1 \text{ mol CO$_2$}} = 0.53 \text{ g CO$_2$}[/tex]

In conclusion, about 0.53 g of carbon dioxide needs to be added.

Answer:

Because noble gases have a full octet, their ionization energies are actually quite high. Electron affinity is the amount of energy released when an electron is added to a neutral atom. Because noble gases have stable electron configurations, they have very low electron affinities.

Explanation:

Answer:

Noble gases have a stable outer shell

Explanation:

Answer:

As a substance changes from a solid to a liquid to a gas, its molecules first the molecules are moving fast enough, they are able to "escape." They leave the surface of the liquid as gas molecules. Evaporation is not the only process that can change a substance from a liquid to a gas. The same change can occur through boiling.

Explanation:

hopfully this helps!

Answer:

C. Aluminum

Explanation:

Aluminum has 5.9858 ionization energy

Boron has 8.298 ionization energy

Silicon has 8.1517 ionization energy

Carbon has 11.2603 ionization energy

Answer:

D. Fission

Explanation:

Induced fission is used to generate nuclear power and for weapons. The products formed during fission gain kinetic energy. It is this energy that is harnessed in nuclear power stations.

Answer:

Knetic

Explanation:

When you jump on a trampoline, your body has kinetic energy that changes over time. As you jump up and down, your kinetic energy increases and decreases with your velocity. Your kinetic energy is greatest, just before you hit the trampoline on the way down and when you leave the trampoline surface on the way up.