5-O selênio e o enxofre pertencem à família VI A da tabela periódica. Sendo assim, o seleneto e o

sulfeto de hidrogênio são representados, respectivamente pelas fórmulas:

a) HSe e HS

b) H 2 Se e HS

c) HSe e H 2 S

d) H 2 Se e H 2 S

e) H 3 Se e H 3 S

Answer:

CaF2

Explanation:

1 mole of CaF2 = 78.0748064 grams

78 times 3.33= 259.74

the others multiplied were nowhere near 260 grams either

Answer:

A

boiling water

Explanation:

The boiling point of water is 212 degrees F. Due to the temperature of the water being this high, the particles are sped up since heat increases kinectic energy.

Answer: 123 g

Explanation: Q =It = nzF. For Ca^2+ z= 2, t = 5.5 x 3600 s and I = 30.0

And F= 96485 As/mol

Amount of moles is n = It /zF = 3.078 mol , multiply with atomic mass 40.08 g/mol

Answer:

2.11 billion years.

Explanation:

I hope this helps! Have a great rest of your day!

Answer:

Sure I'll help you!

Explanation:

The head of the nail is flat and isn't sharp enough to cut anything, If you stab someone with a sword then hit them with a shield would it have the same effect? Of course not.

Answer:

Carbon is an element that's found all over the world and in every living thing. Oxygen is another element that's in the air we breathe. When carbon and oxygen bond together, they form a colorless, odorless gas called carbon dioxide, which is a heat-trapping greenhouse gas. Whenever we burn fossil fuels such as coal, oil, and natural gas—whether it's to drive our cars, use electricity, or make products—we are producing carbon dioxide.

The atmosphere isn't the only part of the Earth that has carbon. The oceans store large amounts of carbon, and so do plants, soil, and deposits of coal, oil, and natural gas deep underground. Carbon naturally moves from one part of the Earth to another through the carbon cycle. But right now, by burning fossil fuels, people are adding carbon to the atmosphere (in the form of carbon dioxide) faster than natural processes can remove it. That's why the amount of carbon dioxide in the atmosphere is increasing, which is causing global climate change.

Explanation:

Answer:

1.3 atm

Explanation:

Apply the ideal gas law: PV = nRT

Since we need to find the pressure, solve for pressure:

P = nRT / V

Plug in our given values of n = 4.6 moles, R = 0.08206 (ideal gas law constant using atm), T = 325 K, and V = 96.8 L:

P = 4.6(0.08206)(325) / 96.8 = 1.267 atm -> 1.3 atm (two significant figures)

Answer:

I think it's thermochemical reaction and sorry if it's wrong

Answer:

57.7 miles.

Explanation:

Hello there!

In this case, according to the given information, it is possible to set up the initial miles-cost ratio as shown below:

[tex]\frac{30mi}{\$2.60}[/tex]

Thus, we can find the the driven miles with $5 by multiplying as follows:

[tex]\frac{30mi}{\$2.60} *\$5\\\\=57.7mi[/tex]

Best regards!

The miles' the car can run with the fuel cost $5 has been 57.69 miles.

The given car run for a 30 miles by 1 gallon of the fuel. The given cost of fuel has been $2.60. Thus, for 30 miles, the cost of fuel has been driven to be $2.60.

The miles that can be driven by the car with $5 has been given by unitary method. The expression has been driven as:

[tex]\$2.60=30\;\rm miles\\\$5=\dfrac{30}{2.60}\;\times\;5\;miles\\\$5=57.69\;miles[/tex]

The miles' the car can run with the fuel cost $5 has been 57.69 miles.

For more information about unitary method, refer to the link:

https://brainly.com/question/11859405

Push and pull subjected to an object is called force and is given in newtons. The net force acting on the race car is -6,256 N.

Force is the product of the mass of the object in kg and the acceleration in meters per second square. It is given by the formula:

[tex]\rm F = m \times a[/tex]

Given,

Mass of the race car = 1,840 kg

Acceleration of the race car = -3.4

Substituting values in the above equation:

[tex]\begin{aligned} \rm F &= \rm m \times a \\\\&= 1840 \times -3.4\\\\&= -6,256 \;\rm N \end{aligned}[/tex]

Therefore, option D. -6,256 N is the force acting on the car.

Learn more about force here:

https://brainly.com/question/16085992

Answer:

82.59 m/s or 297.324 km/h

Explanation:

From the question,

Applying

V = √[2(P'/ρ)].................. Equation 1 ( From

Where V = Speed of the aircraft, Differential Pressure of the air craft, ρ = Density of air at an altitude of 3000 m.

Given: P' = 3100 N/m², ρ = 0.909 kg/m³

Substitute into equation 1

V = √[2(3100/0.909)]

V = √(2×3410.34)

V = √(6820.68)

V = 82.59 m/s

V = 297.324 km/h

Hence the speed of the aircraft is  82.59 m/s or 297.324 km/h

Explanation:

Elements are arranged from left to right and top to bottom in order of increasing atomic number. ... The number of electrons in a period increases as one moves down the periodic table; therefore, as the energy level of the atom increases, the number of energy sub-levels per energy level increases.

Answer:

Suppression

Explanation:

suppression is used to reduce pest populations below the economic threshold if prevention and avoidance tactics have failed--chemical, bio and cultural and other tactics are used which minimize environmental impacts

Answer:

i know im late again but its suppression

Explanation:

Answer:

It is the same it does not change

Explanation:

Explanation:

Homogeneous catalysts are those that occupy the same phase as the reaction mixture (typically liquid or gas), while heterogeneous catalysts occupy a different phase. Generally, heterogeneous catalysts are solid compounds that are added to liquid or gas reaction mixtures.

Answer:

B. the products have more energy than the reactants.

Answer:

6.02*1022

Explanation:

I don't know why

Answer:

4. Daughter nuclide

5. Fusion

6. Strong nuclear force

Explanation:

4. When an atom of an element decays to a new element, the new element is called the

In a radioactive decay in nuclear physics, the product of the decay which is usually smaller (loss in mass) than its source and may or may not be radioactive is the daughter nuclide. Its source is the parent nuclide

5. Nuclear fusion is the nuclear process that involves the combination of two or more (light) atoms to produce subatomic particles and one or more atomic nucleus accompanied by an emission or absorption of energy due to the difference between the weight of the reactants and the weight of the products

The given reaction, is presented as follows;

³₂He + ¹₁H → ⁴₂He + ⁰₁e

Therefore, given that two atoms, (³₂He and ¹₁H) combine to form one atom (⁴₂He) and a subatomic electron particle (⁰₁e), the reaction is a fusion reaction

6. What keeps a nucleus together

The nucleus is made of neutrons and protons. There is an attractive nuclear force between protons and neutrons and a repulsive electromagnetic force between two or more protons. However, due to the proximity of the of the neutrons and the protons, which are together known as the nucleons, the attractive nuclear force is stronger than the electromagnetic force pushing the protons away from each other and the nucleus is kept together

Therefore, the strong nuclear force keeps the nucleus together.

Answer:

247.2g

Explanation:

Using the general gas law equation as follows:

PV = nRT

Where;

P = pressure (atm)

V = volume (L)

n = number of moles (mol)

R = gas law constant (0.0821 Latm/molK)

T = temperature (K)

According to the information in this question, a fuel tank contains 150. L (V) of H2 gas at 20.0 atm (P) at 25.0˚C (T)

Temperature = 25°C = 25 + 273 = 298K

Using PV = nRT

20 × 150 = n × 0.0821 × 298

3000 = 24.4658n

n = 3000/24.4658

n = 122.62

n = 122.6mol

Using the formula, mole = mass/molar mass, to find the mass of H2 gas.

Molar mass of H2 = 1.008(2)

= 2.016g/mol

122.6 = mass/2.016

mass = 122.6 × 2.016

mass = 247.2g.

Answer:

The pool float looked would have looked deflated the next morning.

Explanation:

When temperature decreases the volume decreases.

Answer: In balancing any chemical equations, the number of atoms of each elements on the reactant side is equals to the number of atoms of the elements on the product side.

Explanation:

Balanced Chemical equations are those equations that has the equal number of atoms of elements on both the reactants and the product sides. To ensure that the chemical equations are correctly balanced the following steps should be observed.

--> identify the elements on the reactant side and on the product side

--> identify the number of atoms of each elements.

--> multiply the number of atoms with the number that will give you a coefficient that will make both the reactant and product sides equal.

--> place the new numbers infront of the elements or compounds.

--> A final check is done to know if the equation is balanced.

From the above steps, the balanced equation of the above questions are listed below:

1.) AlBr3 + 3K ---> 3KBr + Al

2.) FeO + PdF2 --> FeF2 + PdO

3.) P4 + 6Br2 --> 4PBr3

4.) 2LiCl + Br2 --> 2LiBr + Cl2

5.) PbBr2 + 2HCl --> 2HBr + PbCl2

6.) 2CoBr3 + 3CaSO4 --> 3CaBr2 + Co2(SO4)3

7.) 2Na3P + 3CaF2 --> 6NaF + Ca3P2

8.) 2Mn + 6HI --> 3H2 + 2MnI3

9.) Li3PO4 + 3NaBr --> Na3PO4 + 3LiBr

10.) CaF2 + Li2SO4 --> CaSO4 + 2LiF

11.) 2HBr + Mg(OH)2 --> MgBr2 + 2H2O

12.) 2LiNO3 + CaBr2 --> Ca(NO3)2 + 2LiBr

13.) AgNO3 + Li --> LiNO3 +Ag

14.) Si(OH)4 + 4NaBr --> SiBr4 + 4NaOH

15.) 2NaCN + CuCO3 --> Na2CO3 + Cu(CN)2

16.) 2NH3 + H2SO4 --> (NH4)2SO4

Answer:

1a 2b 3c 4d 5c 6c that is the answer to your quesrion i believe

1) A 45.7 g sample of glass was brought to thermal equilibrium with boiling water and then transferred to 250.0 g of water that was at 22.5 °C. This combination reached thermal equilibrium at 24.2 °C. What is the specific heat capacity of glass?

2) What mass of silver at 100.0 °C, when added to 150.0 g of water at 21.0 °C, would raise the water’s temperature to 24.0 °C ?

3) The molar heat of fusion of H2O is 6.1 kJ/mole. What amount of energy would be needed to melt 376 g of ice at 0.0 °C?

Answer:

Explanation:

Recall that the density of a gas is its mass to volume ratio,  

ρ

=

m

V

. Therefore, if we can determine the mass of some volume of a gas, we will get its density. The density of an unknown gas can used to determine its molar mass and thereby assist in its identification. The ideal gas law, PV = nRT, provides us with a means of deriving such a mathematical formula to relate the density of a gas to its volume

Answer:

2.01588 grams

Explanation:

Answer: There are 0.000043 moles of melatonin.

Explanation:

According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number [tex]6.023\times 10^{23}[/tex] of particles.

To calculate the moles, we use the equation:

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

given mass = 10 mg = 0.01 g

molar mass of [tex]C_{13}H_{16}N_2O_2[/tex] = 232.28 g

[tex]{\text {moles of melatonin}}=\frac{0.01g}{232.28g/mol}=0.000043moles[/tex]

Thus there are 0.000043 moles of melatonin

Answer:

2.24 M

Explanation:

Molality is a measure of molar concentration of a solution and it can be calculated using the formula;

Molality = mole of solute ÷ kg of solvent

To calculate the number of moles present in the solute, we use the formula;

mole = mass ÷ molar mass

Molar mass of Fe(ClO2)3 = 56 + {35.5 + 16(2)}3

= 56 + (35.5 + 32)3

= 56 + (67.5)3

= 56 + 202.5

= 258.5g/mol

mole = 435/258.5

mole of Fe(ClO2)3 = 1.68mol

750g of solvent = 750/1000 = 0.750kg of solvent

Molality of the solution is thus: 1.68/0.750

Molality = 2.24 M.