Answer:
Xenon- 131
Explanation:
Iodine- 131 ------------------> Xenon -131 + Beta particle
seasonal variation in Earth's climate are caused by
a Earth's rotation
b Earth's tilt
c Earth's magnetic field
d Earth's precession
Answer: B: Earths tilt
Explanation:
Seasonal variation occurs because the Earth is tilted on its axis by 23.5˚. As Earth orbits the sun, its orientation to the sun changes.
The arrows in the chart below represent phase transitions.
Which arrows represent the phase transitions in which heat energy is gained?
1, 2, and 3
2, 3, and 5
3.4. and 5
4.5 and 6
Answer:
a. 1,2,and 3.
Explanation:
When something turns liquid, e.g. metal, you need to heat it. When something turns gas, e.g. water, you need to heat it. And when something goes directly from solid to gas, e.g. dry ice, carbon dioxide, you need to add heat to it. hope this helps! Please mark brainiest.
Which of the measurement contain three significant figure?
Answer:
The answer is explained below
Explanation:
The question is not complete.
The correct question should be like:
Which of the measurement contain three significant figure?
500
395
0.001
0.00100
1 × 10⁻³
5 × 10²
Answer:
The following are rules applied when considering significant figures:
i) All digits are significant excluding zero. E.g of significant digits are 1,2,3,4,5,6,7,8,9
ii) Any zero that appear within or after non zero digits are significant e.g. 200, 1004, 500009
iii) Zeros before non zero digits are not significant. An example shows significant digits bolded 001, 0.0012, 001.56
iv) Zeros that come after non zero digits are significant even if the number is in decimal form. An example shows significant digits bolded 1000, 0.001200, 001.5600
Therefore:
500: It contains three significant digits
395: It contains three significant digits
0.001: It contains only one significant digits
0.00100: It contains three significant digits
1 × 10⁻³: 1 × 10⁻³ = 0.001. It contains only one significant digits
5 × 10²: 5 × 10² = 500. It contains three significant digits
The measurements that contain three significant figure are 500, 395, 0.00100 and 5 × 10²
What is the oxidation state of each element in the compound CaS04? Include +or - in your answer as appropriate
Answer:therefore the oxidation state of sulphur is +6 in the compound CaSO4.
Explanation:
What does percent composition tell you about a molecule?
O A. It tells you the ratio of elements in the molecular formula.
O B. It tells you how the elements are arranged in the molecule.
O C. It gives you the total number of atoms in the molecule.
D. It tells you how much of a molecule is made up of each element.
The chemical formula for barium oxide is BaO. A chemist determined by measurements that 0.065 moles of barium oxide participate in a chemical reaction. Calculate the mass of barium oxide that participates.
Answer:
9.97 g (corrected to 3 significant figures.)
Explanation:
mass = no. of moles x molar mass
Atomic mass of Barium = 137.327; oxygen = 15.999,
so the molar mass of BaO = 137.327 + 15.999
=153.326
Hence, the mass is
0.065 x 153.326
=9.97 g (corrected to 3 significant figures.)
Answer:
9,97 g to the nearest hundredth.
Explanation:
Using the relative atomic masses of Barium and Oxygen:
1 mole of BaO has a mass of 137.327 + 16 = 153.327 g.
So 0.065 moles has a mass of 153.327 * 0.065
= 9.966 g.
Which temperature in Celsius (°C) does this thermometer show? –8° 0° 25° 32°
Answer:
0° Celsius
Explanation:
The thermometer shows 0° Celsius which corresponds to 32° F.
Answer:
0 degrees celsius
Explanation:
just did the test
Which of the following compounds in the main group is a metalloid?
A. Arsenic
B. Potassium
C. Chlorine
D. Indium
Answer:
A. Arsenic
Explanation:
Arsenic is a metalloid. Arsenic has properties of both metals and non-metals that is why it is a metalloid.
Potassium, chlorine, and indium do not have both properties of metals and non-metals, therefore they are not metalloids.
Answer: A
Explanation: have a nice day
The orbital radii of four planets in our solar system is shown in the following table. Orbital Radii Planet Orbital Radii (AU) W 5.2 X 0.72 Y 0.37 Z 19.1 Which planets are likely to be gas giants? W and X X and Y Y and Z W and Z
Answer:
w&x
Explanation:
The planets which are likely to be gas giants are W and X
What is gas giant planet?Gas giant planets are planets which constitutes of only two gases; hydrogen and helium.
However, of all the planetry solar system, there are only four planets which are the major gas giant planets:
UranusNeptuneJupiterSaturnIn conclusion, the planets which are likely to be gas giants are W and X
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What is the mass of a sample of copper that contains 4.78 x 1023 atoms?
Answer:
50.45679
Explanation:
mass of 1 mole(6.02 x 10^23atoms) of copper: 63.546g
so,
63.546g x 4.78 x 10^23 / 6.02 x 10^23 = 50.45679g (you could round this to the nearest decimal if u wish so)
Write the net ionic equation describing the reaction between aluminum metal and Fe3+ ions in solution that produces dissolved Al3+ and Fe2+ ions. Be sure to include all states of matter.
Answer:
Al(s) + Fe³⁺ ----> Al³⁺(aq) + Fe²⁺(aq)
Explanation:
The reaction between aluminium metal with an aqueous solution of Fe³⁺ ions to produce Al³⁺ ions and Fe²⁺ ions is a redox reaction in which the aluminium metal is oxidized while the Fe³⁺ ions are reduced.
Oxidation occurs if the oxidation number of an element or ionic species increases in the positive direction whereas reduction occurs when the oxidation number of the reacting species decreases.
The oxidation number of aluminium increases from 0 to +3 whereas the oxidation number of iron reduces from +3 to =2 in the given reaction.
In a net ionic equation, only the species participating in the reaction are shown.
The equation is given below;
Al(s) + Fe³⁺ ----> Al³⁺(aq) + Fe²⁺(aq)
The rate constant for the first-order decomposition of cyclobutane at 500 °C is 9.2 x 10−3 s−1. How long will it take (in seconds) for 80.0% of a sample of C4H8 to decompose?
The time taken to complete the reaction is 179 seconds.
Rate of reaction?Rate of reaction is the time taken for a reaction to attain completion. From the data presented, we have;
Initial concentration = No
Final concentration = No - (0.8No) = 0.2No
rate constant = 9.2 x 10−3 s−1
time taken = t
Given that;
N =Noe^-kt
0.2No =Noe^-( 9.2 x 10−3 t)
0.2 = e^-( 9.2 x 10−3 t)
ln(0.2) = 9.2 x 10−3 t
t = ln(0.2)/-9.2 x 10−3
t = -1.609/-0.009
t= 179 seconds
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Select the arrangement that indicate the ions in terms of increasing ionic radii
Cl-< F
Na+ < Cl- < F
F < Cl- < Na+
Na+ < F < Cl-
Answer:
The last option, option D is correct.
The order of increasing ionic radii of the three ions given is
Na⁺ < F⁻ < Cl⁻
Check Explanation for reasons why.
Explanation:
For elements in the same group of the periodic table, the ionic radii increases as we move down the group. This is because the number of shells increase as we move further down a group in the periodic table and that automatically confers a bigger radii to the element with the more shells.
So, between F⁻ and Cl⁻, we know the fluoride ion has electronic configuration 2, 8 (2 shells) after it gains an electron to its normal electronic configuration to form the ion, but the chloride ion has electronic configuration 2, 8, 8 (3 shells) when it achieves its own stable octet of outermost electrons.
So, it is clear how Cl⁻ ion has a bigger ionic radii than F⁻ and even Na⁺.
Then, to know which ion is bigger between Na⁺ and F⁻, it is known that when cations and anions have the same electronic configuration, the cations usually have the lesser ionic radii.
This is because in a normal, neutral atom, the number of electrons in the atom matches the number of protons. And the force of attraction between the protons and the electrons matches each other as they both have the same charges and are equal in number.
But cations result from the neutral element losing one or more electrons to achieve that stable octet. This makes the number of protons to exceed the number of electrons, hence, the electrons available are more tightly pulled towards the centre of the atom by the protons in the nucleus of the atom. This results in a reduced ionic radii.
Unlike anions that gain electrons to achieve that stable octet and have the electrons exceeding the protons in their ions, causing the pull of the protons on the electrons to be reduced, thereby resulting in a more repelled electrons pushing the ionic radii further than normal thereby increasing it.
Hope this Helps!!!
If Sulfonamides are toxic to Bacteria by stopping folic acid synthesis, and since folic acid is also very important for humans Does this make Sulfonamides toxic to humans? And why?
Answer:
No
Explanation:
Most Sulfonamides are antibiotics that kill bacteria but not human cells. They work by distrupting the production of dihydrofolic acid (form of folic acid that human/bacteria cells use for protein production).
What must occur in order for a chemical reaction to be specifically classified as endothermic instead of exothermic?
A)Atoms are rearranged.
B)Chemical bonds are formed.
C)Energy is released in the form of heat.
D)Energy is absorbed in the form of heat.
An exothermic reaction creates heat.
The answer would be c) energy is released in the form of heat.
A chemical reaction is classified as exothermic or endothermic based on the direction of heat flow during the reaction
The correct option for what must occur for a reaction to be classified as an exothermic reaction is option C
C) Energy is released in the form of heat
The reasons the above value is correct are;
An exothermic reaction is one in which energy in the form of light, heat or other forms because the sum of the energy in the product is less than the sum of energy contained in the reactants
Therefore, for a chemical reaction to be specifically classified as an endothermic reaction, instead of an exothermic reaction, is energy, in the form of heat (or light) must be released
The correct option is option C
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Balance each of the following chemical equations:
a. N2(g) + O2(g) → NO(g)
b. HgO(s) = Hg(l) + O2(8)
c. Fe(s) + O2(g) →→ Fe2O3(s)
d. Na(s) + Cl2(g) →→ NaCl(s)
e. Cu2O(s) + O2(g)
→ CuO(s)
Answer:
a. N₂(g) + O₂(g) → 2 NO(g)
b. 2 HgO(s) → 2 Hg(l) + O₂(g)
c. 4 Fe(s) + 3 O₂(g) → 2 Fe₂O₃(s)
d. 2 Na(s) + Cl2(g) → 2 NaCl(s)
e. 2 Cu₂O(s) + O₂(g) → 4 CuO(s)
Hope this helps.
hello:) is hydrogen chloride and hydrochloride acid the same??
Answer:
No because hydrogen chloride is gas and hydrochloric acid is (as stated in the name) an acid. The formula for hydrogen chloride is HCI(g), the little g states that the compound is a gas and the formula for hydrochloric acid is HCl(aq) and the little aq means aqueous.
Answer:
no. they are not the same
Explanation: Although, they both do have the same chemical formula HCL, they differ in their states of matter. Hydrogen chloride is a gas whereas hydrochloric acid is a solution of hydrogen chloride gas and water( creates an aquaeous solution). Hydrochloric acid is highly corrossive.
All of the following are units for pressure except _____. A. Pa B. psi C. atm D. Hg
Answer:
B. psi
Explanation:
Pa is Pascal
atm is atmosphere
Hg is Mercury
hope it helps.
Can u please help me , I’m stuck it’s question e
Answer:
salt
Explanation:
xdcfgvh jhg
In an lonie lattice:
A atoms are bonded to four others in a
Tetrahedral shapes
atoma are packed together in a
regular euble arrangement
e. atoms are bonded with a single
bonds and one double bond
D. atoms are structured in a vast
network of atoms
Reset Selection
Answer:
atoms are bonded with a single bond one double bond
Which indicator shows whether a solution is acidic or basic, but not how strong it is?
a)
pH paper
which turns blue in acids and red in bases.
Ob) pH paper which turns red in acids and blue in bases.
c) Litmus paper which turns red in acids and blue in bases.
d) Litmus paper which turns blue in acids and red in bases.
Answer:
Option C
Explanation:
Litmus paper shows only whether the solution is acidic or basic, but not how strong it is.
=> Base turns the red litmus paper blue
=> Acid turns the blue litmus paper red.
The kinetic-molecular theory of gases says A. the particles of a gas move independently of each other. B. the particles in a gas move rapidly. C. the particles in a gas are far apart. D. all of the above.
Answer:
D. all of the above.
Explanation:
The kinetic-molecular theory of gases suggests that; the particles of a gas move independently of each other, the particles in a gas move rapidly, the particles in a gas are far apart.
Hope it helps.
a compound contains 28.6 magnesium 14.3 carbon 57.1 oxygen what is the empirical formula
Answer:
Option 3
[tex]MgCO_{3}[/tex]
Explanation:
These are the steps for empirical forumla
1) If given percentage, assume everything in grams
2) Convert those grams to moles (using specific molar mass of each unique element)
3) Divide all the moles by the smallest mole you discovered.
4) Answer will be close to a whole number for each element and that's the answer.
First step, 28.6 g Mg, 14.3 g C, 57.1 g O
Second step:
28.6/24.305 = 1.1767 Mg
14.3/12.01= 1.1907 C
57.1/16.00 = 3.5688 O
Third step:
1.1767/1.1767 = 1 Mg
1.1907//1.1767 ~ 1 C
3.5688/1.1767 ~ 3 O
Put everything together you get!
[tex]MgCO_{3}[/tex]
The empirical formula for the compound is:
C. [tex]MgCO_3[/tex].
What is an Empirical formula?A chemical formula showing the simplest ratio of elements in a compound rather than the total number of atoms in the molecule.
Given:
28.6 g Mg, 14.3 g C, 57.1 g O
In order to determine empirical formula we will divide mass of each given element with the molar mass of the respective element.
[tex]\frac{28.6}{24.305} = 1.1767 Mg[/tex]
[tex]\frac{14.3}{12.01}= 1.1907 C[/tex]
[tex]\frac{57.1}{16.00} = 3.5688 O[/tex]
Dividing each mass with the lowest mass:
[tex]\frac{1.1767}{1.1767 } = 1 Mg[/tex]
[tex]\frac{1.1907}{1.1767 } = 1 C[/tex]
[tex]\frac{3.5688}{1.1767} =3 O[/tex]
Thus, the empirical formula for the compound is [tex]MgCO_3[/tex].
Therefore, option C is correct.
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For the galvanic (voltaic) cell Fe(s) + Mn2+(aq) → Fe2+(aq) + Mn(s) (E°= 0.77 V at 25°C), what is [Fe2+] if [Mn2+] = 0.040 M and E = 0.78 V?
Assume T is 298 K
Answer:
0.01836 M
Explanation:
Again the reaction equation is;
Fe(s) + Mn2+(aq) → Fe2+(aq) + Mn(s)
E°cell= 0.77 V
Ecell= 0.78 V
[Mn2+] = 0.040 M
[Fe2+] = the unknown
n=2
From Nernst's equation;
Ecell= E°cell- 0.0592/n log Q
0.78= 0.77 - 0.0592/2 log [Fe2+] /[0.040]
0.78-0.77= - 0.0592/2 log [Fe2+] /[0.040]
0.01/ -0.0296= log [Fe2+] /[0.040]
-0.3378= log [Fe2+] /[0.040]
Antilog(-0.3378) = [Fe2+] /[0.040]
0.459= [Fe2+] /[0.040]
[Fe2+] = 0.459 × 0.040
[Fe2+] = 0.01836 M
The Fe ion concentration in the galvanic cell has been 0.0186 M.
The Nernst equation has been used for the determination of the voltage of the galvanic cell.
It can be given as:
[tex]\rm E_c_e_l_l\;=\;E_0\;-\;\dfrac{0.059}{n}\;\times\;log\;\dfrac{[Fe^+]}{[Mn^2^+]}[/tex]
where, n = number of electrons transfer = 2
[tex]\rm E_0[/tex] = initial voltage = 0.77 V
[tex]\rm E_c_e_l_l[/tex] = cell voltage = 0.78 V
Iron ion concentration = 0.040 M
Susbstituting the values:
0.78 = 0.77 - [tex]\rm \dfrac{0.059}{2}\;\times\;log\;\dfrac{[Fe^2^+]}{[0.040]}[/tex]
0.78 - 0.77 = -0.0296 [tex]\rm \times\;log\;\dfrac{[Fe^2^+]}{[0.040]}[/tex]
-0.03378 = [tex]\rm log\;\dfrac{[Fe^2^+]}{[0.040]}[/tex]
antilog (-0.03378) = [tex]\rm \dfrac{[Fe^2^+]}{0.040}[/tex]
Iron ion concentration = 0.0186 M
Thus, the Fe ion concentration in the galvanic cell has been 0.0186 M.
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Iron oxide reacts with carbon monoxide to produce iron and carbon dioxide, with the balanced chemical equation Fe2O3 + 3CO —> 2Fe + 3CO2. What does this tell you
about the relative amounts of iron oxide and iron consumed and produced in this equation?
A. For every two moles of iron oxide consumed, one mole of iron is produced,
B. For every two grams of iron oxide consumed, one gram of iron is produced.
C. For every gram of iron oxide consumed, two grams of iron are produced
D. For every mole of iron oxide consumed, two moles of iron are produced.
Answer:
Option D. For every mole of iron oxide consumed, two moles of iron are produced.
Explanation:
The balanced equation for the reaction is given below:
Fe2O3 + 3CO —> 2Fe + 3CO2
From the balanced equation above,
1 mole of iron oxide, Fe2O3 reacted with 3 moles of carbon monoxide, CO to produce 2 moles of iron, Fe and 3 moles of carbon dioxide, CO2.
Thus, with a careful observation of the equation, we can conclude that for every 1 mole of iron oxide, Fe2O3 consumed, 2 moles of iron, Fe are produced.
Which process describes the passing of nutrient molecules from the digestive system into the blood?
Answer:
The liver has multiple functions, but two of its main functions within the digestive system are to make and secrete an important substance called bile and to process the blood coming from the small intestine containing the nutrients just absorbed. The liver purifies this blood of many impurities before traveling to the rest of the body.
Explanation:
Answer:
"Absorption is the process by which nutrient molecules pass through the wall of your digestive system into your blood. Materials that are not absorbed, such as fiber, are eliminated from the body as wastes."
Explanation:
how many dots would go around xenon in electron dot diagram
Answer:
8
Explanation:
Since Xe (xenon) is a noble gas, it has 8 valence electrons. It's outer shell is full and it is a stable element and doesn't like to react. Therefore, since the electron dot diagram is about valence electrons, 8 would be your answer.
Plz Help me with this ?
Answer:
Hey there!
This is a convergent boundary. Here, a oceanic crust collides with a continental crust.
Hope this helps :)
Cosmone has the molecular formula C15H26O. Calculate the number of moles of carbon in a 8.35-mol sample of cosmone. Calculate the mass of a sample of cosmone that contains 6.58 x 1019atoms of hydrogen. Calculate the number of atoms of carbon m 8.00-g of cosmone.
Answer:
1) 125.25 moles of carbon
2) 9.35 × 10⁻⁴ grams of cosmone
3) 1.44×10²¹ atoms of carbon
Explanation:
1) The given compound, cosmone, with molecular formula C₁₅H₂₆O has 15 toms f carbon per molecule, therefore, we have
8.35 mole of C₁₅H₂₆O, will contain 15 × 8.35 moles of carbon which is 125.25 moles of carbon
2) The number of moles of hydrogen in 6.58 × 10¹⁹ atoms of hydrogen = 6.58 × 10¹⁹/(6.02 × 10²³) = 1.09 × 10⁻⁴ moles
1 mole of cosmone contains 26 moles of hydrogen, therefore;
1 mole of hydrogen will be contained in 1/26 moles of cosmone
1.09 × 10⁻⁴ moles of hydrogen will be contained in 1/26 × 1.09 × 10⁻⁴moles of cosmone = 4.204 × 10⁻⁶ moles of cosmone
The molar mass of cosmone = 15*12.0107 + 26*1.00784 + 1 * 15.999 = 222.36334 g/mol
Therefore, the mass of 4.204 × 10⁻⁶ moles of cosmone = 4.204 × 10⁻⁶×222.36334 = 9.35 × 10⁻⁴ grams of cosmone
3) The number of moles in 8.00 g of cosmone = 8/222.36 = 0.036 moles
Therefore, number of moles of carbon atoms in 0.036 moles of cosmone = 0.036/15 moles which is 0.0024 moles of carbon;
1 mole of carbon atoms contains 6.02 × 10²³ atoms. therefore;
0.0024 moles of carbon will contain 6.02 × 10²³ × 0.0024 carbon atoms which is 1.44×10²¹ atoms of carbon.
1) The number of moles of carbon are 125.25
2) The mass of sample 9.35 × 10⁻⁴ grams
3) The number of atoms of carbon 1.44×10²¹
Calculation for number of moles:1) Molecular formula for cosmone is C₁₅H₂₆O, it has 15 atoms of carbon per molecule, therefore, we have
8.35 mole of C₁₅H₂₆O, will contain 15 * 8.35 moles of carbon which is 125.25 moles of carbon
2) The number of moles of hydrogen in 6.58 × 10¹⁹ atoms of hydrogen
= 6.58 × 10¹⁹/(6.02 × 10²³)
= 1.09 × 10⁻⁴ moles
1 mole of cosmone contains 26 moles of hydrogen, thus;
1 mole of hydrogen will be contained in 1/26 moles of cosmone
1.09 × 10⁻⁴ moles of hydrogen will be contained in 1/26 × 1.09 × 10⁻⁴moles of cosmone = 4.204 × 10⁻⁶ moles of cosmone
The molar mass of cosmone =222.36334 g/mol
Thus, the mass of 4.204 × 10⁻⁶ moles of cosmone
= 4.204 * 10⁻⁶ * 222.36334
Mass of sample = 9.35 × 10⁻⁴ grams of cosmone
3) The number of moles in 8.00 g of cosmone
= 8/222.36
= 0.036 moles
The number of moles of carbon atoms in 0.036 moles of cosmone = 0.036/15 moles which is 0.0024 moles of carbon;
1 mole of carbon atoms contains 6.02 * 10²³ atoms. Thus,
0.0024 moles of carbon will contain 6.02 * 10²³ * 0.0024 carbon atoms which is 1.44 * 10²¹ atoms of carbon.
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please help i need some help with this one plz :)
Answer:
in some animal they changes their body temperature according to the environment temperature. so are called cold blooded animals.they change their temperature for adaptation.