The half-life of bismuth is 5 days. How much of a 100 gram sample will remain after 20 days?
a. 50 grams
b. 12.5 grams
c. 6.25 grams
d. 0 grams
which of these is a chemical property of a substance?
A.texture
B.ductility
C.reactivity
D.conductivity
Write a balanced equation for the reaction of ca with hcl
What are some chemical formulas for compounds?
The chemical formulas for compounds have the information regarding the element present, number of atoms which are present in a compound.
What is a compound?
Compound is defined as a chemical substance made up of identical molecules containing atoms from more than one type of chemical element.
Molecule consisting atoms of only one element is not called compound.It is transformed into new substances during chemical reactions. There are four major types of compounds depending on chemical bonding present in them.They are:
1)Molecular compounds where in atoms are joined by covalent bonds.
2) ionic compounds where atoms are joined by ionic bond.
3)Inter-metallic compounds where atoms are held by metallic bonds
4) co-ordination complexes where atoms are held by co-ordinate bonds.
They have a unique chemical structure held together by chemical bonds Compounds have different properties as those of elements because when a compound is formed the properties of the substance are totally altered.
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Which characteristic is common in young rivers? A. A steep stream. B. Many tributaries. C. Location far from headwaters. D. A wide. U shaped channel
In an ecosystem with young rivers the common characteristic is steep stream as the young rivers do not have other mentioned characteristics.
What is an ecosystem?
Ecosystem is defined as a system which consists of all living organisms and the physical components with which the living beings interact. The abiotic and biotic components are linked to each other through nutrient cycles and flow of energy.
Energy enters the system through the process of photosynthesis .Animals play an important role in transfer of energy as they feed on each other.As a result of this transfer of matter and energy takes place through the system .Living organisms also influence the quantity of biomass present.By decomposition of dead plants and animals by microbes nutrients are released back in to the soil.
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Is sodium hydroxide dissolving in water a physical change?
The carbon-carbon bond in ethylene, h2cch2, results from the overlap of __________. sp3 hybrid orbitals
The carbon-carbon bond in ethylene, h2cch2, results from the overlap of sp2 hybrid orbitals.
The correct option is (D).
1. Hybridization in Ethylene:
- Ethylene [tex](\( \text{H}_2\text{C}=\text{CH}_2 \))[/tex] is a molecule composed of two carbon atoms double-bonded to each other and each carbon atom is also bonded to two hydrogen atoms.
- The carbon atoms in ethylene undergo sp2 hybridization to form the π bond between them.
2. Explanation of sp2 Hybridization:
- In sp2 hybridization, one ( s ) orbital and two ( p ) orbitals of the carbon atom combine to form three sp2 hybrid orbitals.
- These sp2 hybrid orbitals are arranged in a trigonal planar geometry with bond angles of approximately 120 degrees.
- One of the sp2 hybrid orbitals overlaps with an sp2 orbital from the other carbon atom to form the σ bond between the two carbon atoms.
- The remaining two sp2 hybrid orbitals on each carbon atom form sigma bonds with hydrogen atoms.
3. Formation of the π Bond:
- The remaining unhybridized ( p ) orbital on each carbon atom is perpendicular to the plane formed by the sp2 hybrid orbitals.
- These unhybridized ( p ) orbitals overlap laterally to form the π bond between the carbon atoms.
- This lateral overlap of the ( p ) orbitals allows for the formation of the π bond, which is responsible for the double bond character between the carbon atoms in ethylene.
4. Conclusion:
- Thus, the π bond in ethylene results from the overlap of unhybridized ( p ) atomic orbitals, making option D) sp2 hybrid orbitals the correct answer.
complete question given below:
The π bond in ethylene, H2C=CH2, results from the overlap of ________. A) sp3 hybrid orbitals B) s atomic orbitals C) sp hybrid orbitals D) sp2 hybrid orbitals E) p atomic orbitals
What type of molecule is the molecule seen below? ch3—ch2—ch2—ch2 protein nucleic acid sugar lipid hydrocarbon?
He baking soda looked like it dissolved in the vinegar. sarah and connor watched as the balloon expanded and filled with a gas. was this a physical or chemical reaction and why?
Answer:
The answer is chemical reaction- gas produced.
Explanation:
The complete question is:
"The baking soda looked like it dissolved in the vinegar. Sarah and Connor watched as the balloon expanded and filled with a gas. Was this a physical or chemical reaction and why?
A) chemical - gas produced
B) physical - water bottle got hot
C) physical - baking soda dissolved
D) chemical - baking soda disappeared"
A chemical reaction is a process by which one or more substances, called reactants, are transformed into one or more other substances with different properties, called products.
That is, in a chemical reaction, the bonds between the atoms that form the reactants are broken, reorganizing and forming new bonds, thus giving rise to one or more substances different from the initial ones.
Some indications of a chemical change are:
An unexpected color change indicates the formation of new substances when a chemical process takes place. The appearance of precipitates in a solution indicates the formation of a new solid substance that is insoluble and, therefore, deposits at the bottom.Gas evolution: This is evident when spontaneous gas evolution occurs when mixing the reagents. This is what happens when acetic acid (vinegar) is added to solid sodium bicarbonate. Carbon dioxide is produced in the form of bubbles, indicating the chemical reaction. Sudden variations in temperature are also indicators of the presence of a chemical change, due to the energy differences between the reagents and the products.So, the answer is chemical reaction- gas produced.
Does a reaction occur when an aqueous solution of nicl2(aq) is added to a test tube containing strips of metallic zinc?
To know if a reaction would occur, we refer to the reactivity series. Looking at the reactivity series, the zinc is at the upper list than nickel, therefore we could say that a reaction would occur. This would actually be a replacement reaction:
NiCl2 + Zn --> ZnCl2 + Ni
Answer is: yes, reaction occurs.
Reactivity series is an empirical progression of a series of metals, arranged by their reactivity from highest to lowest (alkaline metals have highest reactivity and Noble metals lowest reactivity).
Metal higher in the reactivity series will displace another, zinc is more reactive than nickel.
Chemical reaction: Zn(s) + NiCl₂(aq) → ZnCl₂(aq) + Ni(s).
Ionic reaction: Zn(s) + Ni²⁺(aq) + 2Cl⁻(aq) → Zn²⁺(aq) + 2Cl⁻(aq) + Ni(s).
Net ionic reaction: Zn(s) + Ni²⁺(aq) → Zn²⁺(aq) + Ni(s).
Zinc metal is oxidized (from oxidation number 0 to +2) and nickel is reduced (from oxidation number +2 to 0).
Hydrogen is 99% hydrogen-1; 0.8% hydrogen-2; and 0.2% hydrogen-3. calculate it's average atomic mass
sorry, don't know
sorry, don't know
The azide ion, n−3, is a symmetrical ion, all of whose contributing structures have formal charges. draw three important contributing structures for this ion.
The azide ion N3- can actually be represented by 3 resonance structures.
(check attached image for the structures)
Among the three, the Structure 1 is the most important one. While structure 3 almost makes no contribution due to the positive charges located on the adjacent atoms and the overall higher formal charge.
Azide ion has [tex]\boxed{{\text{three}}}[/tex] resonating structures (For structures, refer to the attached image).
Further Explanation:
The bonding between the different atoms in covalent molecules is shown by some diagrams known as the Lewis structures. These also show the presence of lone pairs in the molecule. These are also known as Lewis dot diagrams, electron dot diagrams, Lewis dot structures or Lewis dot formula. In covalent compounds, the geometry, polarity, and reactivity are predicted by these structures.
When more than one Lewis structures are possible for a single molecule but no single structure is able to explain all the properties of the molecule then resonance is used. All the structures thus formed are called resonating structures and the phenomenon is known as resonance. The resonance structures have the same placement of atoms but different locations of bond pairs and lone pairs of electrons. Moreover, various resonating structures can be converted to each other by moving lone pairs to bonding positions, and vice-versa.
The general rules that we follow to draw the resonance structures are as follows:
a. The [tex]\pi[/tex] electrons or a lone pair of electrons can change their positions while the position of atoms remains fixed.
b. The count of the valence electrons in all the resonating structure should be same.
c. The transfer of electrons is shown by the curved arrows.
d. The resonating structure must follow octet rule that is all atoms should have 8 electrons
Conditions to determine more contributing resonating structures are as follows:
1. Smaller formal charges are always preferred over the larger one.
2. The stable structure has more delocalization of charges on the atoms.
3. A more negative formal charge must always be located on the most electronegative atom.
The resonating structures of azide ion are shown in the image attached.
Structure III is more stable than the other two. This structure has negative charge on more electronegative atom (N) and more delocalization of charge. While in structure I and II, nitrogen is having a positive charge so unstable.
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Answer details:
Grade: Senior School
Subject: Chemistry
Chapter: Resonance
Keywords: resonating structures, azide, N3-, structure I, structure II, structure III, Lewis structures, smaller, larger, electronegative atom.
nitrogen is made up of two isotopes N-14 and N15. given nitrogen’s atomic weight of 14.007 what is the percent abundance of each isotope
The percentage abundance of each isotope, given that nitrogen atomic weight is 14.007, are:
99.3% of N-140.7% of N-15How to calculate the percentage abundance of each isotope?
First, we shall obtain the percentage abundance of N-14. Details below:
Mass of 1st isotope, N-14 = 14Mass of 2nd isotope, N-15 = 15Atomic weight of nitrogen = 14.007Let the percentage abundance of 1st isotope, N-14 (A) =?Thus, the percentage abundance of 2nd isotope, N-15 = 100 - A[tex]Atomic\ weight = \frac{Mass\ \times\ abundance}{100} \\\\14.007 = \frac{14\ \times\ A}{100}\ +\ \frac{15\ \times\ (100 - A)}{100}\\\\14.007 = \frac{14A}{100}\ +\ \frac{1500\ -\ 15A}{100}\\\\14.007 = 0.14A\ + 15\ -\ 0.15A\\\\14.007 - 15 = 0.14A\ -\ 0.15A\\\\-0.993 = -0.01A\\\\A = \frac{-0.993}{y-0.01} \\\\A = 99.3\%[/tex]
Thus,
Percentage abundance of 2nd isotope, N-15 = 100 - A
= 100 - 99.3
= 0.7%
If an acid is splashed on your skin, wash at once with what? lab
Identify the gas particle that travels the slowest . identify the gas particle that travels the slowest . ar h2 xe cl2 f2
The rate of diffusion decreases with increasing molar mass of the gas, therefore the gas diffuses more quickly. As a result, the molar masses will be determined in order to decide which gas will diffuse the fastest. Here Xe has the highest molar mass, so it will be slowest.
According to Graham's law, the rate of effusion of a gas is inversely proportional to the square root of its molar mass, which roughly resembles the rate of diffusion. Light gases thus have a tendency to disperse and effuse at a much faster rate than heavy gases.
Xenon has a molar mass of 131.29 g/mol. Xe is the chemical symbol for xenon. The molar mass of a xenon is equal to its atomic mass because there is only one xenon atom in it.
Thus the correct option is C.
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How many isomeric forms can chloroethylene, c2h3cl, have?
Final answer:
Chloroethylene, or vinyl chloride, does not have isomeric forms due to its unique molecular structure that allows for only one arrangement of its atoms, unlike compounds that can exhibit cis-trans isomerism.
Explanation:
Chloroethylene, often referred to as vinyl chloride, does not exhibit isomerism because its molecular structure allows for only one unique arrangement of its atoms. Unlike compounds such as 1,2-dichloroethene, where the presence of a double bond creates the possibility for cis-trans isomerism due to restricted rotation, chloroethylene's structure does not allow for such variability. The presence of the double bond in chloroethylene binds it in a specific structural configuration, with no alternative spatial arrangements for its atoms, thereby precluding the existence of isomers. In summary, chloroethylene can only exist in one structural form and does not have isomeric forms.
Is cutting a paper snowflake a chemical or physical change and why?
Polarity of bonds and molecules is determined by the ______________ of the atoms involved.
The answer is electromagnetivity
A river has different populations of lampreys and paddlefish. The paddlefish feed on zooplankton, while the lampreys feed on the paddlefish. Humans living around the river hunt the paddlefish. What will happen to the ecosystem if the paddlefish are hunted in excess?
The answer is: The population of paddlefish will decrease, while the population of zooplankton will increase.
The paddlerfish is predator to zooplankton. An decrease in predator (in this example the paddlerfish) will increase the number and genetic variation in a population of zooplankton.
An decrease of food (in this example the paddlerfish) will decrease population of the lampreys.
Hman activity (hunting) decrease population of the paddlerfish.
Which of the group ivb (14) metals is the least active?
Identify the atomic number and the chemical symbol for lead, silver, and gold. drag each item to the appropriate bin.
Answer :
The atomic number of lead is, 82. The chemical symbol of lead is, Pb.
The atomic number of silver is, 47. The chemical symbol of silver is, Ag.
The atomic number of gold is, 79. The chemical symbol of gold is, Au.
Explanation :
Atomic number : It is equal to the number of protons or electrons.
Atomic number = number of protons = number of electrons
Mass number : It is defined as the sum of number of protons and number of neutrons.
Number of neutrons = Mass number - Number of protons
As we know that:
Lead is a metal that belongs to group 14 and period 6. The atomic number of lead is, 82. The chemical symbol of lead is, Pb.
Silver is a transition metal that belongs to group 11 and period 5. The atomic number of silver is, 47. The chemical symbol of silver is, Ag.
Gold is a transition metal that belongs to group 11 and period 6. The atomic number of gold is, 79. The chemical symbol of gold is, Au.
calculate the energy of a gamma ray photon whose frequency is 5.02*10^20 HZ
The energy of a gamma ray photon can be calculated using Planck's equation. Given the frequency of 5.02*10^20 Hz, substituting this and Planck's constant into the equation results in an energy of approximately 3.33 × 10^-13 Joules.
Explanation:The energy of a gamma ray photon can be calculated using Planck's equation: E = hf, where 'E' stands for energy, 'h' is Planck's constant and 'f' is the frequency of the radiation.
The value of Planck's constant is 6.626 × 10^−34 J⋅s (Joules times seconds), and the frequency provided is 5.02*10^20 Hz. Substituting these values into the Planck's equation:
E = (6.626 × 10−34 J⋅s) (5.02 × 1020 Hz) = 3.33 × 10-13 J (Joules)
Thus, the energy of the given gamma ray photon is approximately 3.33 × 10-13 Joules.
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0 B
-1
0 Y
0
4 He
2
0 n
1
Which notation is used to represent gamma decay?
Answer:
Correct answer for Plato users
Explanation:
If monosaccharide has 11 oxygen atoms, how many hydrogen atoms does it contain
Final answer:
In a monosaccharide, the number of hydrogen atoms is usually double the number of carbon atoms. Therefore, if a monosaccharide has 11 oxygen atoms, it likely contains 6 carbon atoms and 12 hydrogen atoms.
Explanation:
In a monosaccharide, the number of hydrogen atoms is usually double the number of carbon atoms. This is because each carbon atom forms bonds with either a hydrogen atom or an oxygen atom. Since the monosaccharide in this question has 11 oxygen atoms, we can assume it has 6 carbon atoms (since glucose, a hexose sugar, has 6 carbon atoms) and thus 12 hydrogen atoms.
Which of the following is equal to 2.0 liters? 200 mL 2,000 cm3 20 m3 20,000 mm3
The three dimensional space occupied by the matter is the volume. Here 2.0 liters of volume is equal to 2000 cm³. The correct option is B.
What is volume?The measure of the capacity that an object holds is defined as the volume. If a beaker can hold 100 mL water then its volume is 100. The ratio of the mass to density of a substance is the volume.
It can be expressed in mL, L, m³, cm³, etc. The SI unit of volume is m³. The equation used to determine the volume is:
Volume = Mass / Density
1 L = 1000 cm³
The volume in liters can be converted into cubic meters by multiplying it with 1000. Then, 2.0 L is:
2 L = 2 × 1000 = 2000 cm³
Hence the volume 2000 cm³ is equal to 2.0 L.
Thus the correct option is B.
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The benefit of fusion is that it:
requires no fuel
produces more energy
yields very little nuclear waste
is easier to control
What trend does the electronegativity have on the periodic table?
What element has the electron configuration of 1s22s22p63s23p64s23d4?
Answer:
Chromium (Cr)
Explanation:
To know this, we first need to know, in which group and period of the periodic table is this element. Then, we can identify the element by calculating the atomic number.
In this case, let's write again the electron configuration:
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁴
Now, with the electron configuration we can know the group in which this element is, the period, and the atomic number which will give us the identity of the element.
The period can be identified, by watching the electron configuration and look into the numbers that accompanies the orbitals (The orbitals are the letters s, p and d), and see which one has the highest number. In this case, we have the 4s² , the number 4 is the highest, so the period of this element is period 4.
Now that we know the period, let's determine the group. The group can be determined, watching the electrons of the last cap of the electron configuration (electrons are the numbers superscripted). Now, if the element pass the 3rd period we have to sum the electrons of the previous d cap. In this case, it was. So, we sum 4 electrons of the d orbytal from the previous cap, and the 2 electrons from the 4s, therefore the group of the element is the group 6 (Or column 6 of the table).
Now we know that it's on group 6 and period 4, the final confirmation will be the atomic number of the element. For this, we have to count all the electrons of all capes in the configuration.
Doing this, we have that the sum of all electrons is:
2+2+6+2+6+2+4 = 24
The atomic number of the element is 24.
So to conclude, the element which electron configuration is 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁴, group 6 and period 4, is Chromium (Cr)
How to solve partial pressure given water vapor pressure?
Final answer:
To solve for the partial pressure of a gas in a mixture that includes water vapor, Dalton's law is used to account for the vapor pressure of water, and the ideal gas law assists in determining the density of water vapor.
Explanation:
To solve a problem involving partial pressure and water vapor pressure, one needs to follow a step-by-step approach. For example, if the water vapor pressure at a specific temperature is provided, such as 2.33 × 10³ Pa at 20.0°C, this value is used as the partial pressure of water vapor in the ideal gas law equation:
PV = nRT,
where P is the pressure, V is the volume, n is the number of moles, R is the universal gas constant, and T is the temperature in Kelvin. To find the density of water vapor in g/m³ which corresponds to the given vapor pressure, one must rearrange the ideal gas law to solve for n/V, which gives the number of moles per cubic meter. The molar mass of water from the periodic table is then used to convert moles to grams, thus obtaining the density. A comparison should be made with the saturation vapor density to verify the result.
An understanding of Dalton's law of partial pressures is integral as it states that the total pressure is the sum of the individual gas pressures. In the case of gas collected over water, the total pressure includes both the gas's pressure and the water vapor's pressure. The actual partial pressure of the gas of interest can be calculated as:
Pg = PTotal - PH₂O
This calculation is vital in contexts where gases are collected over water as in many laboratory settings.
In an atom, the electrons orbiting around the nucleus have what kind of a charge
The electrons orbiting around the nucleus in an atom have a negative electric charge. Together, all of the electrons of an atom create a negative charge that balances the positive electric charge of the protons in the nucleus. Electrons are extremely small.