Answer:
Opção D está correta
Explanation:
Conforme indicado no parágrafo -
o selênio e o enxofre pertencem à família VI A da tabela periódica
Seleneto de hidrogênio - H2Se
Sulfato de hidrogênio - H2S
Portanto, a opção D está correta
The air pressure inside a balloon is 0.783 atm. What is this pressure in mmHg?
Do not include units in your answer.
Answer:
It is the same it does not change
Explanation:
A pool float was filled with air to capacity in the middle of a hot day. The next morning the pool float looked different yet no gas escaped or entered the float. Describe what you think the float looked like in the morning and why it occurred.
Answer:
The pool float looked would have looked deflated the next morning.
Explanation:
When temperature decreases the volume decreases.
A geologist is attempting to date a layer of sedimentary rock. He performs radioactive dating using uranium-235, which has a half-life of 703 million years. He determines that the uranium-235 has undergone 3 half-lives. Approximately how old is the rock?
710 billion years
2.11 billion years
710 million years
235 million years
2.11 million years
none of the above
Answer:
2.11 billion years.
Explanation:
I hope this helps! Have a great rest of your day!
The density of a gas was found to be 19.1 g/L at 2.25 atm and 19.3°C. What is the molar mass of
the gas?
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
4.6 moles of a gas are at a temperature of 325 K and a volume of 96.8 L, what is the pressure of the ga
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)
What is the molality of a solution that contains 435 grams of Fe(ClO 2 3)3 , in 750.0 g of solvent?
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.
A Pitot-static probe is used to measure the speed of an aircraft flying at 3000 m. If the differential pressure reading is 3100 N/m2, determine the speed of the aircraft in m/s. The density of air at an altitude of 3000 m is 0.909 kg/m3. The speed of the aircraft is km/h.
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
What coefficients would balance the following equation?
__Al + __O2 → __Al2O3
A. 2Al + 3O2 → 1Al2O3
B. 2Al + 3O2 → 2Al2O3
C. 3Al + 3O2 → 2Al2O3
D. 4Al + 3O2 → 2Al2O3
How many atoms are in 34.2 grams of carbon?
Answer:
6.02*1022
Explanation:
I don't know why
The measured amount of product obtained from a chemical reaction
is the.
Melatonin has the chemical formula C13H16N2O2. Less than 10 milligrams(0.01g) Convert the melatonin to moles
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
can send me the answer plzzz
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
The fastest man on Earth, Usain Bolt, runs at a speed of 10 meters per second. How
long would it take him to run 160 meters?
How many grams of H2O would be made from 7.9 moles of H2? (Round to one decimal place)
Answer:
2.01588 grams
Explanation:
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?
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?
which is BEST used to describe a chemical reaction that also produces a change in heat?
a. exothermic reaction
b. chemical reaction
c. thermochemical reaction
d. nuclear reaction
will give brainliest
Answer:
I think it's thermochemical reaction and sorry if it's wrong
PLEASE SOMEONE HELP dont mind the answers in there already
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.
Please help me with 1,2,3,4,5,6
Answer:
1a 2b 3c 4d 5c 6c that is the answer to your quesrion i believe
structure of periodic table explain
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.
How would you expect the reaction profile of an endothermic reaction to look?
a. The reactants have more energy than the products.
b. The products have more energy than the reactants.
c. There is no activation energy.
d. The reactants and the products have the same energy.
Answer:
B. the products have more energy than the reactants.
100 pts Horticulture (HURRY)
Which of the following facets of IPM control systems is most likely to focus on the diversion of pests from a commercial crop?
monitoring
avoidance
suppression
prevention
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:
An unknown compound in the lab is either LiOH, CaF2, or LiF. If the sample has a mass of 260 grams and contains 3.33 moles, what is the identity of the compound?
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
How many grams of Ca metal are produced by the electrolysis of molten CaBr2 using a current of 30.0 amp for
5.50 hours?
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
If you have a car that gets 30 miles to the gallon and fuel currently costs $2.60 a gallon, how many miles can you drive if you have 5$ worth of fuel?
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
The driver of an 1,840 kg race car applies the brake to come to a complete stop. If the car
accelerates at -3.4 m/s2 what is the net force acting on the race car?
a) -541 N
b) 630 N
c) -1.8 N
d) -6,256 N
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.
What is force?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
if you push the head of a nail against your skin and then push the point of the same nail against your skin with the same force the point of the nail may pierce your skin while the head of the nail will not why is that
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.
All you need to know about CO2?
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:
New concept cars in the Detroit Auto Show feature engines that burn hydrogen gas in air to produce water vapor. Suppose that fuel tank contains 150. L of H2 gas at 20.0 atm pressure at 25.0˚C. If all of this gas is burned, what mass (in grams) of water vapor is produced?
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.
differentiate between homogenous and heterogeneous catalysis
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.
Please help as soon as possible
The molecules of which of the following would have the most kinetic energy?
A
boiling water
B
a cold glass of water
C
a warm cup of tea
D
an ice cube
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.