Answer:
Radon
Explanation:
n 1908 Ramsay and Gray, who named it niton, isolated the element and determined its density, finding it to be the heaviest known gas. It is essentially inert and occupies the last place in the zero group of gases in the Periodic Table. Since 1923, it has been called radon.
Most of the energy used in the United States comes from
Answer:
Energy in the United States comes mostly from fossil fuels: in 2010, data showed that 25% of the nation's energy originates from petroleum, 22% from coal, and 22% from natural gas.
Explanation:
It is really self explanitory
GOLF BALL PROPERTIES 1. Gabriel uses these numbers to find the density of the golf balls. Water has a density of 1.0 g/cm3. Which ball will float? (D = m/V) Ball Mass (g) 22 18 Volume (cm) 20 20 a) Ball A b) Ball B c) Ballc d) Ball D 30 OA 20 20 33
Answer:
ball B
Explanation:
Ball B with a density of 0.9 g/cm³ will float in water.
Option B is the correct answer.
What is density?Density is mass per unit volume.
Its unit is given as g/cm³.
We have,
The density of Ball A.
= 22 g / 20 cm³
= 1.1 g/cm³
The density of Ball B.
= 18 g / 20 cm³
= 0.9 g/cm³
Now,
Since the density of water is 1.0 g/cm³,
The ball that will float is the one with a density of less than 1.0 g/cm³.
Therefore,
Ball B with a density of 0.9 g/cm³ will float in water.
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Suppose you place a hot pack into a vacuum chamber and the hot pack caused the temperature to rise from 21 degrees to 23 degrees Celsius. If the
pressure was initially 1 atmosphere, what equation would you use to determine the new pressure at the new temperature? Assume volume, and quantity of
gas are held constant.
Select one:
a. P1/T1 = P2/T2
b. P1V1 = P2V2
c. P1T1 = P2T2
d. P1n1 = P2N2
Answer:
A
Explanation:
Pressure and Temperature have to be divided by each each other because they are directly related.
George washes dishes with a new scented dish soap. After washing the dishes, he thinks they
are cleaner using the new scented soap. What can he do to be sure that the new scented
dish soap cleans his dishes better than the old dish soap?
Hint: You will want to set up an experiment, think about all the variables.
1 point-answer attempted
2 points – set up experiment
2 points – correctly identified variables
Answer:
Please find the set up of the experiment below
Independent variable: DISH SOAP
dependent variable: Cleanliness of the dishes
Explanation:
In order for George to be sure that the new scented dish soap cleans his dishes better than the old dish soap, he will set up an experiment using the scientific method.
The scientific method has the following steps:
1) Ask a question: Every scientific experiment starts with a question. I'm this case, George will ask the question that: Does the new scented dish soap clean dishes better than the old dish soap?
2) Formulate a hypothesis: A hypothesis is a testable explanation to an asked question or observed problem. A hypothesis in this case will be: IF the new scented dish soap is used, THEN dishes will be cleaner.
3) Test hypothesis: A hypothesis is tested by conducting an experiment. In this experiment, George will compare the effect of the old dish soap to that of the new scented soap. He will wash a group of plates with the old dish soap and wash another group with the new scented soap. He will then compare how clean the groups of dishes are.
In this experiment, the INDEPENDENT VARIABLE, which is the variable George manipulates is the DISH SOAP while the DEPENDENT VARIABLE, which is the variable George measures is the CLEANLINESS OF THE DISHES.
The control group is the group of dishes washed with the old dish soap while the experimental group is the group of dishes washed with the new scented dish soap.
The control variables of this experiment can be the same type of plates, same color of plates, same type of food eaten with the dishes etc.
4. Conclusion: Concluding in an experiment involves accepting or rejecting the hypothesis depending on the outcome of the experiment. If the outcome aligns with the hypothetical statement, the hypothesis will be accepted but if otherwise, it will be rejected.
What is the composition of nucleotide?
a) a sugar + a phosphate
b) a base + a sugar
c) a base + a phosphate
d) a base + a sugar + phosphate
Answer:
I'm not sure about this question but I think it C
A solute added to a solvent raises the boiling point of the solution because: Select one: a. The solute particles raise the solvent's vapor pressure, thus requiring a higher temperature to cause boiling. b. The temperature to cause boiling must be great enough to boil not only the solvent but also the solute. c. The solute increases the volume of the solution, and an increase in volume requires an increase in the temperature to reach the boiling point (derived from PV
Answer:
See the answer below
Explanation:
The correct answer would be that the solute particles lower the solvent's vapor pressure, thus requiring a higher temperature to cause boiling.
Dissolving a solute particle in a solvent leads to a decrease in the vapor pressure of the solvent above the resulting solution when compared to the pure solvent. The lower the vapor pressure of a liquid, the higher the temperature required for the liquid to boil and vice versa. Hence, a higher temperature would be needed to boil a solvent with dissolved solutes.
How much fluid from the 1:5 dilution has to be transferred to the second microcentrifuge tube containing 900 L buffer to prepare a 1:50 dilution? a. 200 ML b. 100 ML c. 10 ML d. 50 ML
Answer: i think it's d 50 ML
Explanation:
100 mililiters of the 1 : 5 dilution must be transferred to the second microcentrifuge tube containing 900 mililiters buffer to prepare a 1 : 50 dilution. (Correct answer: B)
Reminder - The question has a typing mistake, correct form is presented below:
"How much fluid from the 1 : 5 dilution has to be transferred to the second microcentifuge tube containing 900 mL buffer to prepare a 1 : 50 dilution?"
We can estimate the quantity of the 1 : 5 dilution by means of the Principle of Mass Conservation and definition of Concentration, which are represented by the following expression:
[tex]c_{1}\cdot V_{1} = c_{2} \cdot V_{2}[/tex] (1)
Where:
[tex]c_{1}[/tex] - Initial concentration, in units solute to unit solution.[tex]c_{2}[/tex] - Final concentration, in units solute to unit solution.[tex]V_{1}[/tex] - Initial volume of solution, in mililiters.[tex]V_{2}[/tex] - Final volume of solution, in mililiters.If we know that [tex]c_{1} = \frac{1}{5}[/tex], [tex]V_{1} = x[/tex], [tex]c_{2} = \frac{1}{50}[/tex] and [tex]V_{2} = x + 900[/tex], then the amount to be transferred to the buffer is:
[tex]\frac{1}{5} \cdot x = \frac{1}{50}\cdot (x+900)[/tex]
[tex]10\cdot x = x + 900[/tex]
[tex]9\cdot x = 900[/tex]
[tex]x = 100[/tex]
100 mililiters of the 1 : 5 dilution must be transferred to the second microcentrifuge tube containing 900 mililiters buffer to prepare a 1 : 50 dilution. (Correct answer: B)
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For the following reaction, 8.00 grams of silicon tetrafluoride are allowed to react with 7.40 grams of water. silicon tetrafluoride (s) + water (l) hydrofluoric acid (aq) + silicon dioxide (s) What is the maximum amount of hydrofluoric acid that can be formed? grams What is the FORMULA for the limiting reagent? H2O What amount of the excess reagent remains after the reaction is complete? grams
Answer:
For the following reaction, 8.00 grams of silicon tetrafluoride are allowed to react with 7.40 grams of water. silicon tetrafluoride (s) + water (l) hydrofluoric acid (aq) + silicon dioxide (s) What is the maximum amount of hydrofluoric acid that can be formed? grams What is the FORMULA for the limiting reagent? H2O What amount of the excess reagent remains after the reaction is complete? grams
what is flowering plant
a plant that has flowers and fruits
Are all molecules of a particular substance alike?
Answer:
Yes.
Explanation:
Yes, all molecules of a particular substance are similar or alike if the substance has similar shape and structure. Molecule is made up of two or more atoms having no charge on them and the atoms present in it make bonds with each other. For example, water is made of similar molecules i. e. two hydrogen atom and one oxygen atom bonded together with a covalent bond.
Scientific notation for 782,000 g
Answer:
7.82*10^5
Explanation:
In scientific notation, there is only one number before the decimal and two numbers after, anything after that is counted towards the exponent next to the 10.
Because you move the decimal to the left 5 times to get one number before the decimal (7) your exponent is 5
Hope this helped,
-Kiddoo :)
1. The process of photosynthesis requires a source of carbon dioxide.
HYPOTHESIS: Increasing the concentration of carbon dioxide available to aquatic plants will increase
the rate of photosynthesis, as measured by the number of oxygen bubbles produced.
Independent variable:
Dependent variable:
Answer:
The rate of photosynthesis is the dependent and concentration of carbon dioxide is the independent
Explanation: The rate of photosynthesis depends on how much carbon dioxide is being supplied which makes it the dependent variable.
Hope this helped! :)
The Skeletal System does all of the following except:
Produces Blood Cells
Protects Organs
Stores calcium and minerals
Excretes Waste
The skeletal system does not excrete waste. Therefore, option D is correct.
What is the skeletal system ?The skeletal system is our body's central framework. It is also known as the musculoskeletal system. The skeletal system consists of bones and tendons, and ligaments, connective tissue, including cartilage.
The skeletal system plays an important role in support and protection for the body's internal organs and gives the muscles a point of attachment.
Our circulatory system delivers oxygen-rich blood to your bones. Our skeletal system is depend on our urinary system to remove waste produced by bone cells. The bones of your skeleton create a structure that protects our urinary bladder. Our circulatory system delivers oxygen-rich blood to your bones.
Thus, option D is correct.
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The correct chemical equation for the reaction of sodium bromide and lead nitrate is: _________.
a. NaBr(aq) + Pb(NO3)2aq) ---------->PbBr2ts) + NaNO3(aq)
b. NaBr(aq) + Pb(NO3)2----------> PbBr2(aq) + NaNO3(s)
c. 2 NaBr(aq) + Pb(NO3)2(aq)---------> PbBr2(aq) + NaNO3(s)
d. 2 NaBr(aq) + Pb(NO3)2(aq)---------> PbBr2 + NaNO3(aq)
Answer : The correct chemical equation is:
[tex]2NaBr(aq)+Pb(NO_3)_2(aq)\rightarrow PbBr_2(s)+2NaNO_3(aq)[/tex]
Explanation :
Balanced chemical equation : It is defined as the equation in which the atoms of individual elements present of reactant side must be equal to the product side.
According to the question, when sodium bromide reacts with lead nitrate then it reacts to give sodium nitrate and lead bromide as a products.
The balanced chemical equation will be:
[tex]2NaBr(aq)+Pb(NO_3)_2(aq)\rightarrow PbBr_2(s)+2NaNO_3(aq)[/tex]
Q2. The table gives the composition of three particles.
number of
number
of
number of
electrons
particle
neutrons
protons
A
15
15
16
B
15
18
16
A
с
15
15
17
(a) What is the evidence in the table for each of the following?
Particle A is an atom.
[1]
R.A.
Answer:
The proton and electrons are equal,
15protons and 15electrons
Explanation:
An atom is the smallest electrical neutral particle of an element so it means that every atom have same number of protons and electrons.
Why does density increase with more helium
Answer:
density increases with more helium because of its molar mass
Part 1: Cats falling out of windows
Answer:
A cat that falls out of the window even if it seems to be doing well, must urgently go to a veterinary clinic in order to be placed under surveillance for at least 24 to 72 hours
Explanation:
When an organic molecule loses hydrogen atoms it is said to be:_______.
A) reduced
B) oxidized
C) both oxidized and reduced
D) neither oxidized nor reduced
When a saturated hydrocarbon loss a hydrogen involve an unsaturation it oxidises. Thus, when an organic molecule loses hydrogen atoms it is said to be oxidised.
What is oxidation?Oxidation is the process of loss of electron or loss of hydrogen to change into the higher oxidation state. It can also said that reaction with oxygen is oxidation.
The gain of one or more electrons or hydrogen atoms is called reduction . Reduction make a reactant species in lower oxidation state. The species which is reduced is called reductant and the species which is oxidised is called oxidant.
The group or atom which accepts a hydrogen or electrons from other species and oxidise them is called oxidising agents and the groups which give off their hydrogen or electron to other to reduce them is called reducing agents.
Hence, when an organic molecule loses hydrogen atoms it is said to be oxidised.
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Which metal ions can be precipitated out of solution as chlorides?a. Ag+, Hg2+, Co2+b. Cu2+, Cd2+, Bi3+ c. Ag+, Hg22+, Pb2+ d. Na+, K+, Mg2+
Answer:
Explanation:
In the qualitative analysis of metal salts , we see that in group I , metal chlorides are precipitated out . It is so because their metal chlorides are insoluble in water .
In this group following metal ions are present
Ag+,
Hg₂²⁺
Pb²⁺
Which is not a compound
A.Sugar
B.Water
C.Gold
D.Silicon dioxide
Answer:
C
Explanation:
thats my guess but im not completely sure
The element gold has a consistent melting point and color regardless of the physical changes that it goes through. This identifies gold as what type of substance?
Group of answer choices
A mixture
A physical property
A pure substance
A compound
Answer:
C
Explanation:
The element gold has a consistent melting point and color regardless of the physical changes. This identifies gold as a pure substance. The correct option is C.
What are pure substances?Pure substances are those that are made up of only one type of atom, and nothing is mixed in these substances. They are only one type of particle. They have fixed mass and structure.
Gold is an element that has an atomic number of 79. It is a bright yellow colored and shiny metal. It is used to make an ornament, which is made by mixing other metal to it.
Elements and compounds are subclasses of pure substances. A material that solely contains one type or class of atom is said to be an element. Gold is a pure substance, it is made by one type of atom which is Aurum (Au).
Thus, the correct potion is C. A pure substance.
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A chef is testing out new iron cookware. He knows that iron has a specific heat of
445 J/kg°C. He heats a 2 kg iron skillet on stove for 5 minutes and finds that the
temperature of the iron skillet has increased by 250°C. What change in
temperature will the Chef observe when he heats his 4 kg iron skillet on the same
stove for the same amount of time?
A. An increase of 125°C
B. An increase of 250°C
C. An increase of 325°C
O D. An increase of 445°C
He knows that iron has a specific heat of 445 J/kg°C. He heats a 2 kg iron skillet on stove for 5 minutes and finds that the temperature of the iron skillet has increased by 250°C An increase of 250°C change in temperature will the Chef observe when he heats his 4 kg iron skillet on the same stove for the same amount of time.
What is specific heat ?Specific heat can be defined as the measurable amount of heat needed to increase the temperature of one gram of a substance by one degree Celsius of temperature.
The units of specific heat can be represented as calories or joules per gram per Celsius degree where as 1 calorie per gram per Celsius degree.
Specific heat capacity= Heat quantity/ mass × change in temperature.
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Hydrogen gas, H2, reacts explosively with gaseous chlorine, Cl2, to form hydrogen chloride, HCl(g). What is the enthalpy change for the reaction of 2 mole of H2(g) with 2 mole of Cl2(g) if both the reactants and products are at standard state conditions? The standard enthalpy of formation of HCl(g) is −92.3 kJ/mol. H2(g)+Cl2(g)→2HCl(g)
Answer:
-184.6 KJ/mole
Explanation:
H2(g) + Cl2(g) ------------> 2HCl(aq)
Δ H0 rxn = Δ H0f products - Δ H0f reactants
= 2×-92.3 - (0 + 0)
= -184.6KJ/mole
H2(g) + Cl2(g) ------------> 2HCl(aq) Δ H0rxn = -184.6KJ/mole
Given :
Hydrogen gas,[tex]H_2[/tex] , reacts explosively with gaseous chlorine, [tex]Cl_2[/tex], to form hydrogen chloride, HCl(g).
The standard enthalpy of formation of HCl(g) is −92.3 kJ/mol.
[tex]H_2(g)+Cl_2(g) - >2HCl(g)[/tex]
To Find :
The enthalpy change for the reaction of 2 mole of [tex]H_2(g)[/tex] with 2 mole of [tex]Cl_2(g)[/tex] if both the reactants and products are at standard state conditions .
Solution :
We know ,
[tex]\Delta H^o_{rxn}=\Delta H^{o}f_{products}-\Delta H^of_{reactants}\\\\\Delta H^o_{rxn}=2\times (-92.3)-(0+0)\\\\\Delta H^o_{rxn}=-184.6\ kJ/mol[/tex]
( Since , [tex]H_2[/tex] and [tex]Cl_2[/tex] are their most elementary form . So their enthalpy of formation is 0 kJ )
Therefore , the enthalpy change for the reaction of 2 mole of [tex]H_2(g)[/tex] with 2 mole of [tex]Cl_2(g)[/tex] if both the reactants and products are at standard state conditions is -184.6 kJ/mol .
Hence , this is the required solution .
How did the US government change its policy toward Native American land during the 1850s?
They began to designate all land on the Great Plains as reservation land
They created new treaties and reservations that defined specific boundaries for each tribe
They began to allow Native Americans to hunt on their traditional lands
The started forbidding settlers from claiming any land on the Great Plains
Reduced grazing lands
• Hunting for sport and
Answer:
The correct answer is B) They created new treaties and reservations that defined specific boundaries for each tribe
Explanation:
One of such acts which was used to reallocate the Native American Land was the General Allotment (Dawes) Act of 1887.
It gave permission to the Federal Government to modify the size and ownership structure of land belonging to the Native Americans. The end result was that the total amount of land originally belonging to the Native Americans reduced drastically over the next 500 years.
Cheers!
Hot coffee with sugar (completely dissolved) is classified as?
The table below shows some information about four different elements.
Element
Classification
Density (g/cm³)
barium (Ba)
metal
3.6
beryllium (Be)
metal
1.8
chromium Cr)
metal
7.2
phosphorus P)
nonmetal
1.8
A cube of an unknown element has a shiny, silvery color. The side of the cube measures 2.0 cm and the cube has a mass of 14.56 g.
Based on the information in the table, which element makes up the cube?
barium
beryllium
chromium
phosphorus
Answer:
beryllium
Explanation:
Element (20X) in the periodic table exist in:
It occurs in oxygen I think
Which energy output objects work with the solar panels?
Answer:
In this simulation, you will be able to “see” several different forms of energy and the changes(transfers) that can occur between them.You are also able to work with a system where you canmanipulate the energy input, observe the process of electrical energy generation and manipulatethe output.Click on the “Energy Systems” tab.We will do all of our work here. Be sure to clickthe “Energy Symbols” box so the different types of energy will be visible throughout the process
We have that for the Question "Which energy output objects work with the solar panels" it can be said that the energy output object that works with the solar panels is the
Inverter
From the question we are told
Which energy output objects work with the solar panels?
Generally
Inverter
A Inverter is a device used in a solar installation system,with its primary work being conversion from DC(Direct current) to AC(Alternating Current)
When the panel traps solar energy using photoelectric cells and transfers them to the Inverter converts the DC charge to AC in order to charge the batteryTherefore
the energy output object that works with the solar panels is the
Inverter
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What is the best way to make sure an experiment is precise?
What are the boiling points and freezing points (in oC) of a solution of 50.3 g of I2 in 350 g of chloroform? The kb = 3.63 oC/m, the kf = 4.70 oC/m for CHCl3, and the molar mass of I2 is 253.8 g/mol. The normal boiling point for CHCl3 is 61.2 oC, and the normal freezing point for CHCl3 is -63.5 oC.
Answer:
Boiling point: 63.3°C
Freezing point: -66.2°C.
Explanation:
The boiling point of a solution increases regard to boiling point of the pure solvent. In the same way, freezing point decreases regard to pure solvent. The equations are:
Boiling point increasing:
ΔT = kb*m*i
Freezing point depression:
ΔT = kf*m*i
ΔT are the °C that change boiling or freezing point.
m is molality of the solution (moles / kg)
And i is Van't Hoff factor (1 for I₂ in chloroform)
Molality of 50.3g of I₂ in 350g of chloroform is:
50.3g * (1mol / 253.8g) = 0.198 moles in 350g = 0.350kg:
0.198 moles / 0.350kg = 0.566m
Replacing:
Boiling point:
ΔT = kb*m*i
ΔT = 3.63°C/m*0.566m*1
ΔT = 2.1°C
As boiling point of pure substance is 61.2°C, boiling point of the solution is:
61.2°C + 2.1°C = 63.3°C
Freezing point:
ΔT = kf*m*i
ΔT = 4.70°C/m*0.566m*1
ΔT = 2.7°C
As freezing point is -63.5°C, the freezing point of the solution is:
-63.5°C - 2.7°C = -66.2°C