Answer:
D. 0.75 grams
Explanation:
The data given on the iridium 182 are;
The half life of the iridium 182, [tex]t_{(1/2)}[/tex] = 15 years
The mass of the sample of iridium, N₀ = 3 grams
The amount left, N(t) after two half lives is given as follows;
[tex]N(t) = N_0 \left (\dfrac{1}{2} \right )^{\dfrac{t}{t_{1/2}} }[/tex]
For two half lives, t = 2 × [tex]t_{(1/2)}[/tex]
∴ t = 2 × 15 = 30
[tex]\dfrac{t}{t_{(1/2)}} = \dfrac{30}{15} = 2[/tex]
[tex]\therefore N(t) = 3 \times\left (\dfrac{1}{2} \right )^2 = 0.75[/tex]
∴ The amount left, N(t) = 0.75 grams
Which is an effect of burning fossil fuels?
A. Alkanes are converted to alkenes.
B. Natural gas forms underground.
C. Pollution is released into the atmosphere.
D. Oxygen gas is given off.
Answer:
C
Explanation:
When fossil fuels are burned, they release large amounts of carbon dioxide, a greenhouse gas, into the air.
Burning fossil fuels, such as coal, oil, and natural gas, releases various pollutants into the atmosphere. The correct answer is C. Pollution is released into the atmosphere.
Burning fossil fuels involves the combustion of carbon-based compounds, such as hydrocarbons, present in these fuels. When these fuels are burned, they react with oxygen in the air, releasing energy in the form of heat and producing combustion byproducts.
One significant effect of burning fossil fuels is the release of pollution into the atmosphere. Carbon dioxide (CO₂) is the primary greenhouse gas emitted during the combustion process. It contributes to the greenhouse effect, trapping heat in the Earth's atmosphere and leading to global warming and climate change. These pollutants include carbon dioxide (CO₂), sulfur dioxide (SO₂), nitrogen oxides (NOx), particulate matter, and other harmful substances. These pollutants contribute to air pollution and can have negative effects on human health, ecosystem health, and climate change.
Hence, the correct option is option c.
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Suppose I have enough ingredients to make 25 cookies, but when I go to bake them, I only get 5. What percent yield did I obtain?
Answer:
Explanation:
What is the "theoretical yield" of cookies from each of the "reactants?"
Theor. yield from eggs
=
12
eggs
×
24 cookies
1
egg
=
288 cookies
Theor. yield from vanilla
=
24
tsp vanilla
×
24 cookies
1
tsp vanilla
=
576 cookies
Theor. yield from salt
=
82
tsp salt
×
24 cookies
0.5
tsp salt
=
3936 cookies
Theor. yield from baking soda
=
84
tsp baking soda
×
24 cookies
0.5
tsp baking soda
=
4032 cookies
Theor. yield from chocolate chips
=
3
cups chocolate chips
×
24 cookies
1.333
cups chocolate chips
=
54 cookies
Theor. yield from sugar
=
11
cups sugar
×
24 cookies
0.5
cup sugar
=
528 cookies
Theor. yield from brown sugar
=
4
cups brown sugar
×
24 cookies
0.5
cup brown sugar
=
192 cookies
Finally, "we leave it as an exercise for the student" to calculate that
Theor. yield from margarine = 72 cookies
b. Identify the limiting reactant
The limiting reactant is the amount of chocolate chips because they can produce the smallest amount of cookies.
c. Determine the theoretical yield
The theoretical yield is 54 cookies, because that is all you can get from the chocolate chips provided.
The percent yield obtained on baking the cookies is 20 % and the theoretical yield is 25 cookies.
What is percent yield?Percent yield is defined as the ratio of actual yield to the theoretical yield multiplied by 100. If the actual and theoretical yield are same then the percent yield is 100%.If actual yield is less than the theoretical yield then the percent yield is less than 100%.Reason of this condition arising is the incompletion of reaction or loss of sample during recovery process.
In cases where percent yield is over 100% it indicates that more sample is recovered than the predicted amount.This condition arises when there are other simultaneous reactions taking place leading to the formation of product. It can also arise if there is incomplete removal of impurities from the sample .
As cookies obtained is 5 it is observed yield while 25 is theoretical yield so the percent yield, 5/25×100=20%.
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An electric kettle draws a current of 6.50 A while it is plugged into a 120-V
electrical outlet. What power does the kettle use?
Answer:
780 watts
Explanation:
formula to find power when given amps and voltage
P = A x V
=6.50a x 120V
= 780 W (watts)
Which kind of energy is stored in the chemical bonds of molecules found in
wood?
A. Mechanical energy
B. Potential energy
C. Gravitational energy
D. Kinetic energy
Answer:
B. Potential energy
Explanation:
It's not mechanical energy, because it is not doing work
It's not kinetic energy because it;s not moving
It's not gravitational energy because it is not above the ground
It is potential energy because it is stored energy
What is this picture an example of?
A. carbon cycle
B. nitrogen cycle
C. water cycle
D. ecological succession
PLEASE HELP
Sorry if the picture is bad Quality
Answer:
i think it is D
Explanation:
i dont know what you are learning but ecological succession is the change of enviroment pretty much.
median of 4, 6 ,9 helppp
For the data set 1, 1, 2, 5, 6, 6, 9 the median is 5. For the data set 1, 1, 2, 6, 6, 9 the median is 4.
hope it helps you
Answer:
The median is 6, since it is the mid value of the set
what is a molecular formula ?
Answer:
a formula giving the number of atoms of each of the elements present in one molecule of a specific compound.
Answer ; try to understand in the explanation
Explanation: Molecular Formula Definition: An expression which states the number and type of atoms present in a molecule of a substance. Examples: There are 6 C atoms and 14 H atoms in a hexane molecule, which has a molecular formula of C6H14.
A few substances are arranged in the increasing order of ‘forces of attraction’ between their particles. Which one of the following represents a correct arrangement?
(a) Water, air, wind
(b) Air, sugar, oil
(c) c Oxygen, water, sugar
Answer:
A.
Explanation:
PO WATER,AIR,WIND
what are examples of soluble salts (metal+acids)
Answer:
Chloride salts - made of HCI
Nitrate salts - made of HNO3
Sulfate salts - made of H2SO4
These are all the examples I could think of.
What is the IUPAC name of linkage isomer of [(NH3)3Pt(NO2)]Cl ? (remember it's linkage isomer)
triamminechloroplatinum(II) nitrite
Which of the following reactions would be the fastest?
A large lump of zinc with high concentration of sulfuric acid.
Small strips of zinc with high concentration of sulfuric acid.
Powdered zinc with low concentration of sulfuric acid.
Powdered zinc with high concentration of sulfuric acid.
2 DONT KNOW
Answer:
it should be powdered zinc with high concentration of sulfuric acid
Combination reactions always:
use only one reactant
require oxygen gas
involve an element and an ionic compound
form only one product
Answer:
require oxygen
Explanation:
303.8 liters volume will be occupied by 217.0 grams of methane gas at STP.
True
False
Answer:
False
Explanation:
It will occupy 271.7
Write a balanced half-reaction for the oxidation of solid manganese dioxide to permanganate ion in basic aqueous solution. Be sure to add physical state symbols where appropriate.
Answer:
8 OH⁻(aq) + Mn(s) ⇒ MnO₄⁻(aq) + 4 H₂O(l) + 7 e⁻
Explanation:
Let's consider the following oxidation half-reaction that takes place in basic aqueous solution.
Mn(s) ⇒ MnO₄⁻(aq)
First, we will perform the mass balance. We will add 4 H₂O to the products side and 8 OH⁻ to the reactants side.
8 OH⁻(aq) + Mn(s) ⇒ MnO₄⁻(aq) + 4 H₂O(l)
Finally, we will perform the charge balance by adding 7 electrons to the products side.
8 OH⁻(aq) + Mn(s) ⇒ MnO₄⁻(aq) + 4 H₂O(l) + 7 e⁻
PLEASE HELP!!!!!!
The average number of drops of NaHCO3 in the titration lab was 142. Calculate the number of moles of NaCHO3 that were required to neutralize the CH3COOH in the vinegar.
- 1 mole of acetic acid was required for 2 moles of sodium bicarbonate
- 1 mole of acetic acid was required for 1 mole of sodium bicarbonate
- 2 mole of acetic acid was required for 1 mole of sodium bicarbonate
- 1 mole of acetic acid was required for 3 mole of sodium bicarbonate
Answer: The correct option is 1 mole of acetic acid was required for 2 moles of sodium bicarbonate
Explanation:
We are given:
Average number of drops of sodium bicarbonate = 142
The chemical equation for the reaction of sodium bicarbonate and acetic acid in vinegar follows:
[tex]NaHCO_3+CH_3COOH\rightarrow CH_3COONa+H_2CO_3[/tex]
From the stoichiometry of the reaction:
1 mole of sodium carbonate reacts with 1 mole of acetic acid in vinegar.
Hence, the correct option is 1 mole of acetic acid was required for 2 moles of sodium bicarbonate
How many atoms of oxygen are represented in 2Al 2 (CO 3 ) 3 ?
A. 3
B. 6
C. 9
D. 18
Calcule el peso de cromato sodico, Na2CrO4, necesario para preparar 200g de una disolución al 20% de Na2CrO4
Answer:
40g de cromato sódico serán necesarios
Explanation:
Una solución 20% de Na2CrO4 contiene 20g de Na2CrO4 por cada 100g de solución (Esto es, soluto + solvente). Para preparar 200g de la disolución en mención serán necesarios:
200g solucion * (20g Na2CrO4 / 100g Solución) =
40g de cromato sódico serán necesarios125 cm3 of a solution contains 0.25 moles of the solute. What is the concentration of the solution?
Answer:
Explanation:
125 cm3 -> 0.125 L
M = no. mole / volume (L)
M = 0.25 / 0.125 = 2 M
what is the molecular weight of a gas which diffuses 1/50 as fast as hydrogen
1. The electronic configuration of chlorine is
1. 2,7
II. 2,8,8,7
III. 2,8,7
IV. 2,7,8
Answer:
Chlorine has atomic number 17. Its electronic configuration is 2, 8, 7. It is the second-lightest of the halogens, it appears between fluorine and bromine in the periodic table.
Answer:
III
Explanation:
From the periodic table, Chlorine(Cl) has 17 protons.
And when arranging the proton of elements each shell has a number protons it can take, i.e
2,8,8,8..........
The first shell can only take a maximum of 2 protons while the second shell upwards takes a maximum of 8 protons
Now we want to arrange Chlorine;
1st shell = 2
2nd shell = 8
2 + 8 = 10
17(no. of Chlorine protons) - 10
= 7
therefore,
3rd shell = 7
Therefore,
The electronic configuration of chlorine is
2,8,7
What is S for silicon tetrachloride, SiCl4
S denotes the ''number of shared electron pairs by an atom'', Hence, Silicon shares its 4 electrons with 4 Cl-atoms. Thus the Value of S is 4 in SiCl₄ .It is also known as covalency
What is Covalency ?
The number of covalent bonds that a particular atom can make with other atoms in forming a molecule.
Covalent bond id formed by the sharing of electron between two atoms.
Hence, Silicon shares its 4 electrons with 4 Cl-atoms. Thus the Value of S is 4 in SiCl₄ . It is also known as covalency
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ANSWER FAST
What is the relationship between Ka and Kb with Kw?
(a) The sum of Ka and Kb equals the auto-dissociation constant for water.
(b) The product of Ka and Kb equals the auto-dissociation constant for water.
(c) The quotient of Ka and Kb equals the auto-dissociation constant for water.
(d)The difference of Ka and Kb equals the auto-dissociation constant for water.
What can a nation do to improve the exchange rate of its currency?
A.
try to improve its balance of trade
B.
try to decrease its trade surplus
C.
try to lower its gross domestic product (GDP)
D.
try to export less while importing more
Answer:
A
Explanation:
balance the trades and improving them
Answer:
A:try to improve it's balance of trade
Explanation:
How or why does lead affect bones and teeth?
Answer:
Lead can harm production of blood cells and the absorption of calcium needed for strong bones and teeth, muscle movements, and the work of nerves and blood vessels. High lead levels can cause brain and kidney damage.
thanks
Once lead enters the body, it is distributed to organs such as the brain, kidneys, liver and bones. The body stores lead in the teeth and bones where it accumulates over time. Lead stored in bone may be remobilized into the blood during pregnancy, thus exposing the fetus.
Sketch 10 atoms of aluminum and 6 molecules of oxygen gas in the container on the left. In the right container, sketch the contents after the reaction is complete.
Answer:
Sketch 10 atoms of aluminum and 6 molecules of oxygen gas in the container on the left. In the right container, sketch the contents after the reaction is complete.
Explanation:
The balanced chemical equation of the reaction is:
[tex]4Al + 3 O_2 -> 2Al_2O_3[/tex]
Though there are 10 atoms of Al, only four atoms will react with every three molecules of oxygen.
Hence, right side the product formed is --- Al2O3.
The diagram shows the basis for forming which of the following?
O nucleic acids
O proteins
O polysaccharides
O lipids
Different between organic fertilizer and inorganic fertilizer
Organic fertilizers are made from mined rock minerals, and natural plant and animal materials. They include ingredients like manure, guano, dried and powdered blood, ground bone, crushed shells, finely pulverized fish, phosphate rock, and wood.
Inorganic fertilizer is synthetic, comprised of minerals and synthetic chemicals. Most of the minerals in inorganic fertilizer are mined from the earth, and balanced inorganic fertilizers are high in all three macronutrients and can contain ammonium sulfate, magnesium sulfate, and potassium chloride.
mark me brainliesttt :))
Which statement best describes the diagram
Explanation:
the answer will be A
The catalyst cannot be at point A since that's the reactant
Pathway B requires more energy, which makes it slower and harder for the reaction to finish
point D is the product
What type of structure are ionic lattices?
Big structures
Small structures
Tiny structures
Giant structures
Answer:
Giant structures
Explanation:
An ionic compound is a giant structure of ions. The ions have a regular, repeating arrangement called an ionic lattice . The lattice is formed because the ions attract each other and form a regular pattern with oppositely charged ions next to each other.
1 point
Write the equation for when aluminum oxide breaks down to yield aluminum and oxygen. What are the coefficients in this balanced equation? (Note: Be sure to
keep the reactants and products in the order that they appear in the question)
Answer:
Al + O2 ------> Al + 2O
Explanation:
hope this helps :)
A balanced equation is the representation of the elements with their symbols and coefficients. The balanced reaction for aluminum oxide is 2Al₂O₃ → 4Al + 3O₂.
What is a balance equation?A balanced equation represents the chemical elements along with their coefficients. The reactants are written on the left side while the products of the reaction are written on the right side of the arrow.
The balanced equation for decomposition reaction for aluminum oxide as,
The unbalanced equation is,
Al₂O₃ → Al + O₂
Oxygen atoms are balanced on both sides of the equation as,
2Al₂O₃ → Al + 3O₂
Now, the number of aluminum is balanced on both sides as,
2Al₂O₃ → 4Al + 3O₂
Therefore, the balanced equation is 2Al₂O₃ → 4Al + 3O₂.
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