Answer:
4 2/3 days
Explanation:
31.25 = 250 ( 1/2)^n solve for n
31.25/250 = 1/2 ^n log both sides to find n = 3 half lives
14 days = 3 half lives
14/3 = 4 2/3 day half life
Which salt is produced when sulfuric acid and calcium hydroxide react completely.
Answer:
calcium sulphate and water
What mass loss would you expect from a reaction between 10.04g of calcium carbonate and 20cm3 of 1m hydrochloric acid
Based on the law of conservation of mass, there is no loss in mass in the reaction, however carbon dioxide gas is evolved.
What is the law of conservation of mass?The law of conservation of mass states that for a chemical change occurring, the sum of masses before and after the reaction is constant.
Based on the law of conservation of mass, the reaction between 10.04g of calcium carbonate and 20cm3 of 1m hydrochloric acid will have the same mass before and after the reaction. Any change in mass will be due to evolution of carbon dioxide gas.
Therefore, there is no loss in mass in the reaction, however carbon dioxide gas is evolved.
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The lewis electron dot system represents electrons in the--
a) outer energy level
b) inner level
c) core level
d) middle level
Answer:
the correct answer is a. the lewis structure represents only the outer energy level
what is the atomic number of sodium
The atomic number of sodium atom (Na) is 11.
What is atomic number?Atomic number of any atom is denoted by the symbol Z, and it is equal to the number of protons or electrons present in that atom.
In the sodium atom, number of proton is equal to 11 and number of electrons is also equal to 11. So the atomic number of sodium atom is 11.
Hence atomic number of sodium is 11.
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The atomic number of sodium is 11.
1. The atomic number of an element represents the number of protons in the nucleus of its atom.
2. Sodium is an element with the symbol Na, and its atomic number can be found on the periodic table.
3. Locate sodium (Na) on the periodic table. It is in the third period and belongs to Group 1, also known as the alkali metals.
4. The atomic number is usually displayed above or below the element's symbol. In the case of sodium, the atomic number is 11.
5. Therefore, the atomic number of sodium is 11. It means that a neutral sodium atom has 11 protons in its nucleus.
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How do you think the light would travel if the laser pointer was 1000 meters away?
20 pnts!!!!!!!!!!!!!!!!!!!!!
It totally depends on the laser power (mW). The divergence of the light is depending on it.
What is a laser?A device that uses stimulated emission of photons from excited atoms or molecules to produce a strong beam of coherent monochromatic light is a laser.
When electrons in optical materials like glass, crystal, or gas absorb energy from an electrical current or light, a laser is formed.
When a 5mW 650 nm laser glows on a white surface in complete darkness, we can see it from 500 to 1 km distant.
Because of the divergence, the projected dot 1 km distant will be a huge dot with a diameter of 20–30 m30 m and will be extremely dim.
Hence,It totally depends on the laser power (mW). The divergence of the light is depending on it.
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Write the chemical formula for cobalt (II) bromide. Asp
Answer:
CoBr2
Explanation:
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Why do fireworks produce heat when they explode?
Iron(|||) chloride can be produced by the reaction shown in the equation
2 Fe + 3 Cl₂ ---> 2 FeCl₃
calculate the maximum mass of iron(|||) chloride(FeCl₃) that can be produced from 11.20g of iron
Relative atomic masses (Ar): Cl =35.5 ; Fe=56
Answer:
Here down below is the equation
Explanation:
Iron (III) chloride can be produced by the reaction shown in this equation:
2Fe +3C2 (arrow) 2FeCl3
Calculate the maximum mass of Iron (III) chloride that can be produced from 11.20 grams of iron?
Relative atomic masses: Cl= 35.5 , Fe =56
The maximum mass of iron(|||) chloride(FeCl₃) that can be produced from 11.20g of iron is 0.069 grams.
What is mass?Mass can be defined as inertia is a quantitative measure of a fundamental feature of all stuff.
It can also be defined as weight is defined as the force exerted by an item while mass is defined as the amount of matter in an object.
The SI unit of mass is kilogram or gram.
Mass can be expressed as
Mass = Given mass of substance / Formula mass
Mass of substance = 11.20 g
Formula mass of FeCl₃ = 162.2
So, mass = 11.20 g / 162.2 g
= 0.069 grams
Thus, the maximum mass of iron(|||) chloride(FeCl₃) that can be produced from 11.20g of iron is 0.069 grams.
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A way of describing a chemical change that indicates what substances were present before the change and what substances are present after the change is called a _____.
A. chemical equation
B. chemical formula
C. chemical bond
D. All of the above
E. None of the above
Answer:
[tex]\\ \rm\dashrightarrow Chemical\: Equation [/tex]
Explanation:
When a chemical change happens or chemical reaction happens something yields at reactants and something at products
Representing them is called chemical equation
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How does pH of acids compare to pH of water?
pH of acids are higher than the pH of water.
pH of acids are lower than the pH of water.
Answer:
see below
Explanation:
water pH ~ 7 acids are less than 7 bases are > 7
I'm going to give brainlyest (image below)
Answer:
it stays the same
Explanation:
Even though the volume of water changes as it becomes ice, the mass of the water should remain the same before and after it turns into ice.
What is the best choice for cleaning up a water filter used in the filtration of unknown small particles from polluted stream water
Answer:
Reverse Osmosis
Explanation:
Reverse osmosis systems are able to remove more contaminants than carbon, making them a popular choice for many consumers.
What was in Flint's water that caused 12 people to die?(1 point)
lead
total triahalomethanes
Legionella pneumophila
Escherichia coli
The presence of lead in Flint's water is what caused the death of 12 people.
Option A.
What was in Flint's water?The Flint water crisis started in 2014 when the city of Flint, Michigan, switched its water source from Lake Huron to the Flint River as a cost-cutting measure.
The water from the Flint River was more corrosive and caused lead to leach from the pipes, contaminating the drinking water. This led to high levels of lead in the drinking water, which is a potent neurotoxin that can cause a variety of health problems, particularly in children.
The contamination also led to an outbreak of Legionnaires' disease, a severe form of pneumonia, which was linked to at least 12 deaths in the area.
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If the ant-lion (predator) population becomes larger than the ant (prey) population what do you think would happen to the population of the ant-lion?
Answer:
It would decrease.
Explanation:
This is because there is not enough food (ant) for the ant-lion group.
Why is the bermuda triangle deadly? or is it just a myth?
Answer:
Its neither a myth nor deadly
Explanation:
Bizarre hexagonal clouds forming above the Bermuda Triangle may be the reason why dozens of ships and planes have mysteriously vanished in the notorious patch of sea, according to scientists.
According to the new theory, clouds over the Bermuda Triangle are like “air bombs” strong enough to cause ship and plane wrecks. The strange “hexagonal” shaped clouds were discovered using radar satellite imagery, which were between 20 and 50 miles wide forming over the water.
What happens during stage 3 of cold water immersion.
Answer:
Stage 3 or long-term immersion hypothermia happens after 30 minutes or more. Cold water pulls heat from the body, and the body’s core temperature drops. This eventually leads to loss of consciousness and death.
H+ ion concentration of 2.5 x 10-5
Answer:
What is the hydrogen ion concentration of a solution labeled "Solution A", whose pH is 5.60?
Tutorial
In this problem we are given pH and asked to solve for the hydrogen ion concentration. Using the equation, pH = − log [H+] , we can solve for [H+] as,
− pH = log [H+] ,
[H+] = 10−pH,
by exponentiating both sides with base 10 to "undo" the common logarithm. The hydrogen ion concentration of "Solution A" is,
[H+] = 10−5.6 ≈ 0.0000025 = 2.51 × 10−6 M.
We can always check our solution by computing −log (2.5 × 10−6) ≈ 5.6.
A police siren passes you with a frequency of 5000 Hz. Which correctly describes the sound wave after the police car passes you? The speed of sound is 340 m/s.
A. siren wavelength of 0.0068 meters, frequency you hear = less than 5000 Hz
B. siren wavelength of 0.0068 meters, frequency you hear = 5000 Hz
C. siren wavelength of 0.0068 meters, frequency you hear = more than 5000 Hz
D. siren wavelength of 5000 meters, frequency you hear = 5000 Hz
Answer:
siren wavelength of 0.0068 meters, frequency you hear = less than 5000 Hz
Explanation:
Q.A police siren passes you with a frequency of 5000 Hz. Which correctly describes the sound wave after the police car passes you? The speed of sound is 340 m/s.
(a) siren wavelength of 0.0068 meters, frequency you hear = less than 5000 Hz
(using doppler's effect)
What is the Doppler effect?Doppler effect is the apparent difference between the frequency at which sound or light waves leave a source and that at which they reach an observer, caused by the relative motion of the observer and the wave source.
Who discovered the Doppler Effect?Christian Johann Doppler, an Austrian mathematician, and physicist discovered the Doppler effect in 1842.
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What is the wavelength of an electromagnetic wave that has a frequency of
1.82 x 1018 Hz in a vacuum? (The speed of light in a vacuum is 3.00 × 108
m/s.)
O A. 6.07 × 109 m
OB. 5.46 × 1026 m
OC. 5.49 x 10-19 m
OD. 1.65 x 10-10 m
The wavelength of an electromagnetic wave that has a frequency of 1.82 x 10¹⁸ Hz in a vacuum is 1.65 × 10-¹⁰m.
How to calculate wavelength?The wavelength of a wave can be calculated by dividing the speed of the wave by its frequency.
According to this question, a wave has a frequency of 1.82 x 10¹⁸ Hz in a vacuum and speed of light in a vacuum is 3.00 × 10⁸ m/s.
wavelength = 3 × 10⁸ ÷ 1.82 × 10¹⁸
wavelength = 1.65 × 10-¹⁰m
Therefore, the wavelength of an electromagnetic wave that has a frequency of 1.82 x 10¹⁸ Hz in a vacuum is 1.65 × 10-¹⁰m.
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What pressure is exerted by 0.375 mol of hydrogen gas in a 4.33 L container at 55.0C?
Answer:
47
Explanation:
lead ions and magnesium ions both have a charge of 2+. predict the ionic equation for this reaction.
As both the ions have charge of +2 the compound formed is PbMg as the like charges will cancel out each other.
What are ions?An ion is defined as an atom or a molecule which has a net electrical charge. There are 2 types of ions :1) cation 2) anion . The cation is the positively charged ion and anion is the negatively charged ion . As they are oppositely charged they attract each resulting in the formation of ionic bond.
Ions consisting of single atom are mono-atomic ions while which consists of two or more ions are called as poly-atomic ions . They are created by chemical interactions . They are very reactive in their gaseous state and rapidly react with oppositely charged ions resulting in neutral molecules.Ions of opposite charges combine in ionic compounds.
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What is the phase of water at 0.5 atm and 100°C?
Water
(liquid)
Water vapor
(gas)
Temperature (°C)
Pressure (atm)
1-
0.5-
0.25-
0
OA. Gas
OB. Liquid
O C. Solid
OD. Gas and liquid
10
Ice
(solid)
0.01
100
The phase of water at 0.5 atm and 100°C is gaseous phase.
What is water phase?
Water exists in three different phases such as liquid, gas, and solid.
The phase of the given water can be determined using phase diagram at standard temperature and pressure as shown in the image uploaded.
At 0.5 atm and 100 °C, the water is still in vapour or gaseous phase.
Thus, the phase of water at 0.5 atm and 100°C is gaseous phase.
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What is the process of removing salt from seawater.
Answer:
Explanation:
Process of desalination is used to remove salt from seawater for provision of fresh water
Calculate the molarity of a 1.0l solution that contains 96g of nahco3
Answer:
1.1 M
Explanation:
The formula mass of sodium hydrogen carbonate is about 23+1+12+3(16)=84 g/mol, so 96 g is about 1.142 mol.
molarity = (moles of solute)/(liters of solution) = 1.1 M
a given mass of gas occupies 500 cm³ at 25° C calculate the temperature in degree Celsius at which its volume becomes doubled at constant pressure
At constant temperature, if the volume of the gas is doubled, the pressure also doubles. The new pressure of the gas is 50°C.
What is Charles's law?Charles's law states that "the volume occupied by a definite quantity of gas is directly proportional to its absolute temperature.
It is expressed as;
V₁/T₁ = V₂/T₂
Given that;
Initial volume of gas V₁ = 500cm³Initial temperature of gas T₁ = 25°CIf final volume is double of initial volume.
Final volume V₂ = 2 × 500cm³ = 1000cm³Final temperature T₂ = ?V₁/T₁ = V₂/T₂
V₁T₂ = V₂T₁
T₂ = V₂T₁ / V₁
T₂ = ( 1000cm³ × 25°C ) / 500cm³
T₂ = 25000m³°C / 500cm³
T₂ = 50°C
At constant temperature, if the volume of the gas is doubled, the pressure also doubles. The new pressure of the gas is 50°C.
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CH4(g) + 2O2 (g) →CO2(g) + 2H2O (l), ΔH = -890kj/mol
Calculate much heat is released when 3.5 moles of methane gas undergo a combustion reaction
A combustion reaction is a reaction that reacts with oxygen to produce the product. 3.5 moles of methane release - 3115 kJ/mol of heat.
What is a combustion reaction?A combustion reaction is a chemical reaction that involves the burning of the reactant in the presence of the oxygen molecule to release heat.
The balanced reaction of methane combustion is given as:
CH₄(g) + 2O₂ (g) → CO₂(g) + 2H₂O (l), ΔH = -890 kJ/mol
From the reaction, it can be said that 1 mole of methane combusts to produce -890kJ/mol enthalpy.
So, 3.5 moles will produce, 3.5 × -890kJ/mol = - 3115 kJ/mol.
Therefore, 3.5 moles of methane produce - 3115 kJ/mol heat.
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0.006kg ball is moving 5.0m/s How large is the kinetic energy from this motion?
Answer: times it by 5
Explanation:
Stacy made the following table to compare the functions of plant and animal structures, but she is missing a row title. Which of the following would best replace the X?
a table comparing the functions of different animal and plant structures. There is an unknown 'X' in the table. The skeleton in animals and the stem in plants provide support. The fur in animals and the waxy covering in plants provide protection. The ovaries in animals and the pistil in plants make 'X'
Answer:
female reproductive structures
I need help I will give crown
Answer:
This is a scientific model.
Explanation:
A scientific model is a representation of systems of ideas, events or processes.
This drawing offers explanations that enables the water cycle to be predicted.
Which compound could serve as a reactant in a neutralization reaction?.
Answer:
In this type of neutralization reaction, the acids and bases are the reactants, since they are the materials that will react to form a new solution. The products are water and salt since they have been created following the reaction.
Explanation:
Neutralization occurs when a strong acid and a strong base come together in a chemical reaction to form water and salt.
In chemistry, acids and bases are measured on the pH scale, which ranges from 0 to 14. Pure water sits in the middle, at a neutral 7. Anything below 7 is an acid, and anything above 7 is a base. Often, solutions are either too acidic or too basic, so a reaction must take place in order to achieve neutralization.
That neutralization leads to the formation of water and salt. In chemistry, salt doesn’t necessarily just mean table salt. It is also a broader term that categorizes the compound that is created in the reaction between an acid and a base.
