Answer:
8 significant figures
Explanation:
All numbers (that are not zero) are always significant. Because there is a zero at the end of the number after the decimal place, this makes this zero also significant. This zero is significant because it makes the number more precise. Therefore, all of the numbers in this number are significant.
Answer:
There are 8 sig figs
Explanation:
describe 2 ways of salting out proteins
The phenomenon known as "salting-out" occurs at very high ionic strengths, when protein solubility declines as ionic strength rises. As a result, salting out may be used to segregate proteins according to how soluble they are in salt solutions.
Because large levels of sodium chloride disturb the bonds and structure of the active site, the rate of enzyme activity will gradually decrease as the concentration of sodium chloride rises. As a result, some of the active sites get denaturized and the starch loses its ability to attach to them. As more enzymes get denatured and eventually cease to function, enzyme activity will steadily wane.
A metal object with mass of 22.7 g is heated to 97.0 ∘C and then transferred to an insulated container containing 84.7 g of water at 20.5 ∘C. The water temperature rises and the temperature of the metal object falls until they both reach the same final temperature of 24.3 ∘C. What is the specific heat of this metal object? Assume that all the heat lost by the metal object is absorbed by the water.
The specific heat of the metal object with a mass of 22.7g heated to to temperature of 97.0°C and then transferred to an insulated container containing 84.7 g of water at 20.5 ∘C is 0.815J/g°C
How to calculate specific heat?
The specific heat capacity of a metal can be calculated using the calorimetry equation as follows:
Q = mc∆T
Where;
Q = quantity of heat absorbed
m = mass of substance
c = specific heat capacity
∆T = change in temperature
mc∆T (water) = -mc∆T (metal)
84.7 × 4.18 × 3.8 = - (22.7 × c × -72.7)
1345.375 = 1650.29c
c = 0.815J/g°C
Therefore, the specific heat of the metal object with a mass of 22.7g heated to to temperature of 97.0°C and then transferred to an insulated container containing 84.7 g of water at 20.5 ∘C is 0.815J/g°C.
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If a snail crawls at a rate of 228.16cm/s, what is its speed in miles per hour?
If a snail crawls at a rate of 228.16cm/s, Its speed in miles per hour will 5.10 miles/hour
What is speed ?
The rate at which someone or something moves or operates or is able to move or operate.
Snail covers distance in 1 seconds = 228.16 cm
It covers in 60 seconds (1 min) = 228.16 cm x 60 = 6mtrs
It covers in 60 minutes (1 hour) = 228.16 cm x 60 x 60 = 821376 cm
Now, lets convert cm to miles :
As, 1 cm = 6.21371 x 10⁻⁶ miles
Thus, 821376 cm = 5.10 miles
hence, If a snail crawls at a rate of 228.16cm/s, Its speed in miles per hour will 5.10 miles/hour
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Enter the coefficient of C₂H6O that correctly balances the equation:
C₂H60+302 → 2CO2 + 3H₂O
Answer:
1 C₂H₆O
Explanation:
The given equation:
C₂H₆O + 3 O₂ ---> 2 CO₂ + 3 H₂O
Reactants: 2 carbon, 6 hydrogen, 7 oxygen
Products: 2 carbon, 6 hydrogen, 7 oxygen
As you can see, the amount of each element on both sides is identical. Therefore, the reaction is already balanced. This means that the coefficient in front of C₂H₆O is 1. When writing the equation, writing the one is insignificant and usually left out.
Pb + 02 - Pb304 help
Answer:
6PbO +O2 --> 2Pb3O4
Explanation:
The question is incomplete I assume it is
PbO + 02 - Pb304
What is the role of a catalyst in a chemical reaction?
A increase the concentration of reactants
B increase the rate of the reaction
C increase the temperature of a reaction
D increase the pressure applied to the reaction
A catalyst is a substance that increases the rate of a chemical reaction by lowering the activation energy without itself being consumed by the reaction.
• How did your experimental absolute zero value compare to the accepted value?
The experimental absolute zero value is less when compared to the accepted value of absolute zero.
What is absolute zero?Absolute zero is defined as the temperature in which the lowest energy possible is attained in a thermodynamic system.
Absolute zero temperature has an accepted values of 0 Kelvin or -273.15 degrees Celsius.
At absolute zero, it is assumed that the volume of an ideal gas becomes zero. However, it has not been possible to cool any gas to absolute zero.
Based on the graph of temperature against volume of gases, the experimental absolute zero extrapolated from the graph where volume of the gases becomes zero is -285 degrees Celsius.
Therefore, the experimental absolute zero value is less when compared to the accepted value.
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Answer:
The experimental absolute zero value is less when compared to the accepted value of absolute zero.What is absolute zero?Absolute zero is defined as the temperature in which the lowest energy possible is attained in a thermodynamic system.Absolute zero temperature has an accepted values of 0 Kelvin or -273.15 degrees Celsius.At absolute zero, it is assumed that the volume of an ideal gas becomes zero. However, it has not been possible to cool any gas to absolute zero.Based on the graph of temperature against volume of gases, the experimental absolute zero extrapolated from the graph where volume of the gases becomes zero is -285 degrees Celsius.Therefore, the experimental absolute zero value is less when compared to the accepted value.
Explanation:
Assume that you measured exactly 2.0 mL of the sodium chloride solution into a small test tube. How many moles of
sodium chloride are in the tube?
Predict the shape of the molecule.
The Correct option is A. octahedral
because the molecule has 6 sigma bonds that results into sp³d² hybridization.
and octahedral structure is formed
Answer:
Octahedral
Explanation:
You have a atom connected to 6 others and each of the bonds are similar
If aluminum has a density of 2.7 g/cm³, what is the volume of 2.7 grams of aluminum?
Answer:
Solution Density of aluminium = 2.7 g/Cm 3 In kg/ m 3 = 27 × 1000 10 =2700 kg/ m 3
Explanation:
Not much of one
Is CaO a molecular compound?
Answer:
It's a Ionic compound
Explanation:
To tell if CaO (Calcium oxide) is ionic or covalent (also called molecular) we look at the Periodic Table that and see that Ca is a metal and O is a non-metal. When we have a metal and a non-metal the compound is usually considered ionic.
Because we have a metal and non-metal in CaO there will be a difference in electronegativity between the metal and non-metal. This difference results in an electron(s) being transferred from the metal (lower electronegativity) to the non-metal (higher electronegativity). The results in the metal becoming a postitive ion and the non-metal a negative ion. The two opposite charges are attracted and form the ionic bond between atoms in Calcium oxide.
A cubic meter of air was sampled at 1.0 ATM and 40 C.
An ion chromatographic analysis of that sample found it to contain 12 micrograms of NO2.
How many ppb of NO2 is in the air?
The amount of nitrogen oxide in the air sample is determined as 7.01 ppb.
Amount of Nitrogen oxide in the air
The amount of Nitrogen oxide (NO2) in the air in parts per billion (ppb) is calculated as follows;
12 micrograms of NO2 = 12 μg = 12 x 10⁻⁶ g
PV = nRT
V = nRT/P
Where;
V is volume of NO2 gasn is number of moles of NO2 gasT is temperature = 40 C = 313 Kn = m/M
M = molar mass of NO2 = 46
n = 12 x 10⁻⁶/46
n = 2.73 x 10⁻⁷ mole
V = (2.73 x 10⁻⁷ x 0.082057 x 313)/(1)
V = 7.01 x 10⁻⁶ L
V = 7.01 x 10⁻⁹ m³
Amount of NO2 In parts per billion= (Volume of NO2)/(volume of air) x 10⁹
= (7.01 x 10⁻⁹)/(1) x 10⁹
= 7.01 ppb
Thus, the amount of nitrogen oxide in the air sample is determined as 7.01 ppb.
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A group of students measure the length of a pencil using a metric ruler. The pencil has a known length of 14.2 cm. They record the following measurements: 13.7 cm, 13.6 cm, and 13.7 cm. What is the best way to describe their data?
a. Accurate, but not precise
c. BOTH accurate and precise
b. Precise, but not accurate
d. NEITHER accurate nor precise
Answer:
Neither accurate not precise
Corrosion may be regarded as the destruction of metal by:
Electrochemical action
Hydroelectric action
Electromechanical action
All of the above
among these properties of acids basses or both which property is specific to acids only? A. accepts protons B. bitter taste C. electricity conductive D. slippery feel
Answer:
C. electricity conductive
How much 5.50M NaOH must be added to 680.0 mL of a buffer that is 0.0215 M acetic acid and 0.0270 M sodium acetate to raise the pH to 5.75?
5.50M NaOH must be added to 680.0 mL of a buffer, The amount of NaOH is mathematically given as
V=2.107mL
What is the volume of 5.50M NaOH?Generally, the equation for Chemical Reaction is mathematically given as
CH3COOH+OH^{-} ⇄ CHCOO^{-} + H2O
Therefore
pka=-log(1.8*10{-5})
pKa=5-0.25527
pKa=4.3447
Hence
[tex]pH=pKa+log\frac{CH3COO}{CH3COOH}\\\\0.75=4.7447+log\frac{0.01564+x}{0.01428-x}[/tex]
x=0.0115898
Volume of NaOH
V=0.0021072L
V=2.107mL
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Assume that a normal curve is a good model for this data set. If 10,000 more observations were collected, what percentage of the observations would be greater than 98.02? In other words, what percentage of the area under the normal distribution curve would lie above 98.02 on the x-axis?
A) 5.9%
B) 2.96%
C) 2.5%
D) 0.0%
The percentage of the area under the normal distribution curve would lie above 98.02 on the x-axis is 2.5 % , option C is the answer.
What is Normal Distribution ?Normal Distribution is a probability distribution which is symmetric about the mean , The frequency is more near the mean and less far from the mean.
It is given in the data that
10,000 more observations were collected
the percentage of the observations would be greater than 98.02 = ?
According to the 68-95-99.7 rule,
It states that approximately
68% of the observations lie within σ of µ
95% of the observations lie within 2σ of µ.
99.7% of the observations lie within 3σ of µ.
The percentage of the observation between various intervals is attached in the image in the answer.
2.1 percent of the population is distributed in the intervals between two and three standard deviations , which is the zone above 2SD and below 3SD.
As 2.1 % is approximate , Therefore from the given option , 2.5%
The percentage of the area under the normal distribution curve would lie above 98.02 on the x-axis is 2.5 % , option C is the answer.
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Avogadro's number is the number of atoms or molecules in one mole of any substance. In other words, a mole is 6.02X1023 of some chemical unit. The size of the chemical unit does not change Avogadro’s number. An analogy can be made using eggs. You can buy small, medium, or large eggs. The size of the eggs doesn’t affect how many eggs are in one dozen. Similarly, the size of the representative particle doesn’t affect how many are in one mole. Describe your own analogy to show the relationship between moles and the size of representative particles.
Please help me make analysis scheme flow chart for the detection of cation present in my unknown salt mixture of Ag+, Pb2+, or Ca2+ cations based on their solubility in the given reagents.
I can only use these reagents: Na2CO3, NaCl, & Na2SO4
The suspected cations in the unknown cation mixture are: Ag+, Pb2+, or Ca2+.
I used 0.5 M solution of all these reagents.
My test results are:
Na2CO3: 20 drops of sodium carbonate were used and silver blue precipitate was produced.
NaCl: 20 drops of sodium chloride were used and no precipitate was formed.
Na2SO4: 20 drops of sodium sulfate were used yellow precipitate was produced.
Please please help me make analysis flow chart based on this information and also tell me in what sequence these reagents will be added to unknown salt mixture.
I suspect that the cation may be Ca2+ based on solubility rules. But I'm not sure.
The possible action your solution might contain is amongst [tex]Ag^+[/tex], [tex]Pb^{2+}[/tex], or [tex]Ca^{2+}[/tex].
What are the solutions?A solution is a homogeneous mixture of one or more solutes dissolved in a solvent.
NaCl: 20 drops of NaCl were used and no precipitate was formed.
No precipitation formed means the [tex]Cl^-[/tex] cation is soluble in water. From your chart, you might see the halide of [tex]Ag^+[/tex] and [tex]Pb^{2+}[/tex] is insoluble in water, which means they should have formed precipitation but you didn't. This means there's less possibility it contains [tex]Ag^+[/tex] or [tex]Pb^{2+}[/tex], so we are left with only [tex]Ca^{2+}[/tex]. Let's confirm it with the rest.
[tex]Na_2SO_4[/tex] : 20 drops of [tex]Na_2SO_4[/tex] were used yellow precipitate was produced.
Even though all other sulfates form precipitation ( Insoluble in water)
[tex]Na_2CO_3[/tex] : 20 drops of sodium carbonate were used and the silver-blue precipitate was produced.
It seems all of their Carbonate is insoluble in nature. ( which is our case too ).
From the above result, only the reaction with NaCl was deemed to be decisive and it indeed contains [tex]Ca^{2+}[/tex] ions. Means you are correct.
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Complete combustion of 8.60 g of a hydrocarbon produced 26.5 g of CO2 and 12.2 g of H2O. What is the empirical formula for the hydrocarbon?
The empirical formula of the hydrocarbon is [tex]C_2H_3[/tex] if combustion of 8.60 g of a hydrocarbon produced 26.5 g of [tex]CO_2[/tex] and 12.2 g of [tex]H_2O[/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 [tex]CH_2O[/tex] is the empirical formula for glucose.
1 mole of carbon dioxide contains a mass of 44 g, out of which 12 g are carbon.
Hence, in this case the mass of carbon in 8.46 g of [tex]CO_2[/tex]:
([tex]\frac{12}{44}[/tex]) × 8.46 = 2.3073 g
1 mole of water contains 18 g, out of which 2 g is hydrogen;
Therefore, 2.6 g of water contains;
([tex]\frac{2}{18}[/tex] × 2.6 = 0.2889 g of hydrogen.
Therefore, with the amount of carbon and hydrogen from the hydrocarbon, we can calculate the empirical formula.
We first calculate the number of moles of each,
Carbon = [tex]\frac{2.3073}{12}[/tex] = 0.1923 moles
Hydrogen = [tex]\frac{0.2889}{1}[/tex]= 0.2889 moles
Then, we calculate the ratio of Carbon to hydrogen by dividing by the smallest number value;
Carbon : Hydrogen
[tex]\frac{0.1923}{0.1923}[/tex] : [tex]\frac{0.2889}{0.1923}[/tex]
1 : 1.5
(1 : 1.5) 2
= 2 : 3
Hence, the empirical formula of the hydrocarbon is [tex]C_2H_3[/tex].
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Plutonium-239 undergoes alpha decay and has a half-life of 24,000 years. After 72,000 years, how much of an initial 100.0 g sample will remain?
A. none
B. 50.0 g
C. 25.0 g
D. 12.5 g
11C. Potassium hydrogen phthalate is a solid, monoprotic acid frequently used in the laboratory to standardize strong base solutions. It has the unwieldy formula of KHC8H4O4. This is often written in shorthand notation as KHP .If 3.41 grams of KHC are needed to exactly neutralize 31.2 mL of a potassium hydroxide solution, what is the concentration of the base solution?
13B.
H3AsO4 + H2C2O4—--------2CO2 + H3AsO3+ H2O
In the above redox reaction, use oxidation numbers to identify the element oxidized, the element reduced, the oxidizing agent and the reducing agent.
name of the element oxidized:
name of the element reduced:
formula of the oxidizing agent:
formula of the reducing agent:
For the reactants,
The oxidation number of hydrogen = +1The oxidation number of oxygen = -2The oxidation number of arsenic = +5The oxidation number of carbon = +3For the products,
The oxidation number of hydrogen = +1The oxidation number of oxygen = -2The oxidation number of arsenic = +3The oxidation number of carbon = +4Here, arsenic (+5 to +3) and carbon (+3 to +4) are the only oxidation numbers changing.
Note that an increase in oxidation number means electrons are lost. Thus oxidation is occurring, and a decrease in oxidation number means electrons are being gained, and thus reduction is occurring.
Also, the compound that contains the element being oxidized is the reducing agent, and the compound that contains the element being reduced is the oxidizing agent.
So, the answers are:
name of the element oxidized: Carbon
name of the element reduced: Arsenic
formula of the oxidizing agent: [tex]\text{H}_{3}\text{AsO}_{4}[/tex]
formula of the reducing agent: [tex]\text{H}_{2}\text{C}_{2}\text{O}_{4}[/tex]
A student uses a solution of 1.2 molar sodium hydroxide (NaOH) to calculate the concentration of a solution of sulfuric acid (H2SO4). She records a neutral pH after adding 20 mL of the sodium hydroxide solution to 50 mL of the sulfuric acid solution.
What is the concentration of the sulfuric acid solution?
A.
0.24 M
B.
0.12 M
C.
2.1 M
D.
1.0 M
E.
0.48 M
From the calculations, the concentration of the acid is 0.24 M.
What is neutralization?The term neutralization has to do with a reaction in which an acid and a base react to form salt and water only.
We have to use the formula;
CAVA/CBVB = NA/NB
CAVANB =CBVBNA
The equation of the reaction is; 2NaOH + H2SO4 ----> Na2SO4 + 2H2O
CA = ?
CB = 1.2 M
VA = 50 mL
VB = 20 mL
NA = 1
NB = 2
CA = CBVBNA/VANB
CA = 1.2 M * 20 mL * 1/ 50 mL * 2
CA = 0.24 M
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BaCl2(aq)+Na2SO4(aq)⟶BaSO4(s)+2NaCl(aq)
Using the balanced chemical equation, determine how many moles of NaCl will be produced, if 0.731 mol of BaCl2 is allowed to react with an excess of Na2SO4.
Answer:
1.46 moles NaCl
Explanation:
To find the moles of NaCl, you need to multiply the given value (0.731 moles BaCl₂) by the mole-to-mole ratio of the two relevant molecules. This ratio is made up of the coefficients in the balanced reaction. The numerator should contain moles NaCl to allow for the cancellation of moles BaCl₂. The final answer should have 3 sig figs to reflect the given value.
1 BaCl₂(aq) + Na₂SO₄(aq) ---> BaSO₄(s) + 2 NaCl(aq)
0.731 mole BaCl₂ 2 moles NaCl
--------------------------- x ------------------------- = 1.46 moles NaCl
1 mole BaCl₂
If 0.731 mol of BaCl₂ is allowed to react with an excess of Na₂SO₄, 1.462 moles of NaCl will be produced.
The balanced chemical equation is:
BaCl₂(aq) + Na₂SO₄(aq) → BaSO₄(s) + 2NaCl(aq)
The mole ratio of BaCl₂ to NaCl is 1:2. This means that 1 mole of BaCl2 will produce 2 moles of NaCl.
Moles of BaCl₂ = 0.731 mol
Mole ratio BaCl₂:NaCl = 1:2
Moles of NaCl = 0.731 mol * 2 = 1.462 mol
If we have 0.731 moles of BaCl₂, then we will produce 2 * 0.731 = 1.462 moles of NaCl.
Therefore, 1.462 moles of NaCl will be produced.
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A boy throws a stone vertically up into the air. What are the energy changes that take place as the stone falls to the ground?
Answer/Explanation:
The boy's muscle energy changes into potential energy due to the height. it then converts into kinetic energy as it goes further upwards into the air.
A hydrocarbon contains 87,8% carbon and
12.2% hydrogen by mass. Its empirical
formula is?
C= 87.8 : 12 = 7.316
H= 12.2 : 1 = 12.2
C : H = 1 : 1.667 = 3 : 5
C₃H₅
Aqueous Copper (II) nitrate reacts with aqueous potassium iodide to form Copper (II) iodide solid and potassium nitrate
Answer:
Cu(NO₃)₂ (aq) + 2 KI (aq) ---> CuI₂ (s) + 2 KNO₃
Explanation:
When writing the reaction with the symbols, you need to take into account the charges of the ions. If he charges on the ions do not balance out in a molecule, they need to be made up for in the form of subscripts. For example, copper (+2) and iodine (-1) have charges which do not balance. Thus, to make the molecule neutral, you need to have two iodine atoms (CuI₂).
The unbalanced equation:
Cu(NO₃)₂ (aq) + KI (aq) ---> CuI₂ (s) + KNO₃
Reactants: 1 copper, 2 nitrate, 1 potassium, 1 iodine
Products: 1 copper, 1 nitrate, 1 potassium, 2 iodine
The balanced equation:
1 Cu(NO₃)₂ (aq) + 2 KI (aq) ---> 1 CuI₂ (s) + 2 KNO₃
Reactants: 1 copper, 2 nitrate, 2 potassium, 2 iodine
Products: 1 copper, 2 nitrate, 2 potassium, 2 iodine
If the earth were the size of an apple, which piece would best represent the amount of mass of the
atmosphere?
O the skin
O the meat
O the stem
O Oops..... I am sorry. I just ate the Pacific Ocean by mistake.
O a seed
How many moles are in 24 g of carbon
Answer:
[tex]\fbox {2 moles}[/tex]
Explanation:
Relation between grams of Carbon and moles :
[tex]\fbox {12 g Carbon = 1 mole}[/tex]
Multiply both sides by 2 :
⇒ 1 x 2 moles = 12 x 2 g
⇒ 2 moles = 24 g
Lisa made observations of stars at different times of the year. She noticed a lot of patterns in the fall, while she couldn't find any patterns in the summer. Why might this be?
This is because fall has more weather patterns which are repetitive than summer.
What is Weather?This is defined as the atmospheric condition of a particular place at a given period of time.
The repetitive weather patterns have various effects on the stars which is why they were studied.
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