Answer:
For one atom of lithium -6 I will need_16.85____ atom of lithium -7 for an average atomic mass of 6.944 .
Explanation:
1 ) Let required atom be m .
[tex]\frac{6\times 1 + 7\times m}{1 + m} = 6.944[/tex]
6 + 7m = 6.944 + 6.944m
7 m - 6.944 m = .944
.056 m = .944
m = 16.85
Here, we are required to find how many atoms of lithium -7 is to combine with 1 atom of lithium -6 for an average atomic mass of 6.944.
For one atom of lithium -6 I will need 16.86 atoms of lithium -7 for an average atomic mass of 6.944.
Let the total number of lithium -6 and lithium -7 required be; x.
Therefore, the number of lithium -7 required is;
(x-1)
Therefore;
{(1/x) × 6 + ((x-1)/x)× 7} = 6.944
Therefore, (6 + 7x - 7)/x = 6.944
And, 7x -1 = 6.944x
0.056x = 1
And, x = 1÷0.056 = 17.86 atoms.
Therefore, the number of lithium -7 atoms needed is;
x - 1 = 17.86 - 1 = 16.85 atoms of lithium -7.
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what does control mean in scientific method
Answer:
A scientific control is an experiment or observation designed to minimize the effects of variables other than the independent variable. This increases the reliability of the results, often through a comparison between control measurements and the other measurements.A scientific control is an experiment or observation designed to minimize the effects of variables other than the independent variable. This increases the reliability of the results, often through a comparison between control measurements and the other measurements.
Explanation:
Let's all give it up for GOOGLE! where you can literally get an answer to something.
think about an inflated balloon and a small bag of marbles that is half its size . which one has more volume explain
The object with more volume is the inflated balloon
Explanation:
Volume is about how much space an object or material occupies; in this context, if the inflated balloon has the double size of the bag of marbles then the balloon has more volume because this is occupying more space.
Moreover, the volume should not be confused with other factors such as mass or weight because it is likely the marbles weight more but this does not imply the marbles have more volume. Also, the balloon contains gas and gases tend to expand and occupy more space, which does not occur with solids such as marbles because these have a defined volume.
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Look carefully at the structural drawing for ethanol above.
How many carbons (C) does an ethanol molecule have?
2
3
6
1
HELPPPPPPPP
Answer:c
Explanation: it's easy
Archimedes tells us the lifting power of a balloon (how much mass it can lift) is equal to the difference between the mass of the balloon and the mass of the air it displaces. That is, if the balloon occupies the same volume as 10 kg of air, but the balloon only weighs 2 kg, then the balloon can lift 8 kg. gas densityH2 0.09 kg/m3He 0.18 kg/m3Air 1.23 kg/m3 Airships have sometimes been filled with hydrogen (H), but hydrogen is very flammable, and after the Hindenburg caught fire and crashed in 1937 with serious loss of life airships have nearly always been filled with helium (He) instead. Suppose a new airship Star of Balogna will have the shape of a cylinder 40. m long, with a radius of 4.0 m, and will weigh 750. kg without any gas inside it. Suppose also the average passenger weighs 80 kg. Calculate how many passengers the Balogna could carry if it were filled with hydrogen, and also if it were filled with helium. Passengers with Hz: 29Passengers with He: 26
Answer:
the Balogna could carry 19 passengers if filled with Hydrogen.
the Balogna could carry 17 passengers if filled with Helium.
Explanation:
Given that:
the radius of the cylinder r = 4.0 cm
the height h = 40 m
the volume of the cylinder will be:
[tex]V = \pi r^2 h[/tex]
V = π (4.0 m)² (40)
V = 2010.62 m³.
where the density of the air = 1.23 kg/m³
the mass of the displaced air = Volume V ×density of the air
= 2010.62 m³ × 1.23 kg/m³
= 2473.0626 kg
To calculate how many passengers the Balogna could carry if it were filled with hydrogen, we have the following:
We are given the density of H₂ to be = 0.090 kg/m³
Therefore, the mass of Helium in the balloon = Volume V × density of the hydrogen
= 2010.62 m³ × 0.090 kg/m³
= 180.9558 kg
The total mass of the balloon = mass of H₂ + mass of empty balloon.
The total mass of the balloon = (180.9558+ 750) kg
= 930.9558 kg
Now, the Mass difference = mass of the air displaced -total mass of the balloon.
the Mass difference = (2473.0626 - 930.9558 ) kg
the Mass difference = 1542.1068 kg
∴
number of persons = mass difference/ mass of passenger
the number of persons = 1542.1068 kg /80 (kg/person)
the number of persons = 19.27 persons
the number of passengers [tex]\simeq[/tex] 19 passengers.
To calculate how many passengers the Balogna could carry if it were filled with helium, we have the following:
We are given the density of Helium to be = 0.18 kg/m³
Therefore, the mass of Helium in the balloon = Volume V × density of the hydrogen
= 2010.62 m³ × 0.18 kg/m³
= 361.9116 kg
The total mass of the balloon = mass of Helium + mass of empty balloon.
The total mass of the balloon = (361.9116 + 750) kg
= 1111.9116 kg
Now, the Mass difference = mass of the air displaced -total mass of the balloon.
the Mass difference = (2473.0626 - 1111.9116 ) kg
the Mass difference = 1361.151 kg
∴
number of persons = mass difference/ mass of passenger
the number of persons = 1361.151 kg /80 (kg/person)
the number of persons = 17.01 persons
the number of passengers [tex]\simeq[/tex] 17 passengers.
SN1 reactions of the type, Nu- + RL → Nu–R + L-, are favoured:a. when tertiary substrates are used. b. by using a high concentration of the nucleophile. c. when L- is a strong base. d. by use of an aprotic solvent.
We can see each other in the classroom right now because we
a.reflect visible light
b. absorb visible light
c.reflect infrared light
d.absorb radio waves.
Answer:
The answer is A
Reflect visible light
When neurotransmitter is released into the synaptic cleft, it is taken up by the post-synaptic neuron.
Answer:
Plz make me brainliest
Explanation:
The neurotransmitters released into the cleft diffuse through it to reach the post-synaptic neuron. Neurotransmitters remain in cleft for only some time. They are either taken up by the presynaptic neuron or are broken down by the enzymes present in the synaptic cleft. The post-synaptic neuron contains several receptors on its plasma membrane
Carry out the following. Please help!
A. 10^4 X 10^5
B. 10^4 X 10^-5
C. 10^4 / 10^5
Answer:
A. 10^9
B. 10^-1
C. 10^-1
Choose all the answers that apply.
Which of the following statements are true?
Ethical scientists make unbiased conclusions.
A dishonest scientst has a lot of integrity.
Confirmation bias is the most common type of bias in science.
Science is based on opinion and subjective evidence.
Bias can be ruled out when similar results are obtained from repeated experiments.
Explanation:
A dishonest scientst has a lot of integrity.
Confirmation bias is the most common type of bias in science.
Answer: ethical scientists make unbiased conclusions, science is based on opinion and subjective evidence, and bias can be ruled out if similar results are obtained from repeated experiments.
Explanation: If you’re a dishonest scientist you don’t have integrity and confirmation bias isn’t the most common type of bias in science
Which atom is most likely to form a metallic bond?
aluminum (Al)
helium (He)
phosphorus (P)
carbon (C)
Answer:
I would say it's A just because it's make no sense for the other answers.
Aluminum atom is most likely to form a metallic bond.
METALLIC BONDS:
Metallic bonds are the kind of bonds that forms between metallic atoms. Electrons are shared between the positive ions called cations. These electrons are called localized electrons. Metallic bonds are responsible for the properties possessed by metals such as conductivity, lustre etc. Since metallic bonds forms between metal atoms, it is most likely to form between aluminum atom.Learn more: https://brainly.com/question/20511339?referrer=searchResults
The oxides of nitrogen are very important ingredients in determining urban air pollution. Name each of the following compounds.(a) N2O(b) NO(c) NO2(d) N2O5(e) N2O4
Answer:
(a) N₂O - Dinitrogen monoxide or Dinitrogen (I) oxide
(b) NO - Nitrogen monoxide or Nitrogen (II) oxide
(c) NO₂ - Nitrogen dioxide or Nitrogen (IV) oxide
(d) N₂O₅ - Dinitrogen pentoxide
(e) N₂O₄ - Dinitrogen tetraoxide.
Explanation:
To name each of the compounds,
(a) N2O; It is properly written as N₂O. N₂O is a colorless, sweet tasting gas also known as "laughing gas".
N₂O - Dinitrogen monoxide OR Dinitrogen (I) oxide.
(b) NO; NO is a colorless gas.
NO - Nitrogen monoxide OR Nitrogen (II) oxide.
(c) NO2; It is properly written as NO₂
NO₂ is a reddish-brown gas.
NO₂ - Nitrogen dioxide or Nitrogen (IV) oxide.
(d) N2O5; It is properly written as N₂O₅
N₂O₅ is a white solid.
N₂O₅ - Dinitrogen pentoxide.
(e) N2O4; It is properly written as N₂O₄;
N₂O₄ is a red-brown liquid with an unpleasant smell.
N₂O₄ - Dinitrogen tetraoxide.
Which of the following pairs exhibit an ion-dipole interaction? a. CH_3OH and Na^+ b. Cl^- and K^+ c. CH_3CH_2CH_2CH_2CH_3 and CH_3CH_2CH_2CH_2COOH d. CH_3CH_2OH and H_2O
Answer:
a. CH_3OH and Na^+
Explanation:
Ion-dipole interaction is the forces of attraction existing between a polar compound and an ion. This particular type of ion-dipole attraction occurs between an electrostatic attraction of an ion and a dipole molecule.
From the given example, CH3OH is a polar compound, and Na^+ is an ion. Therefore, that is the only pair that exhibit the characteristics of an ion-dipole interaction.
A compound contains 16.7 g of iridium and 10.3 g of selenium, what is its empirical formula?
Answer:
THE EMPIRICAL FORMULA OF THE COMPOUND IS Ir Se2
Explanation:
Iridium = 16.7 g
Selenium = 10.3 g
Total mass = 16.7 + 10.3 = 27 g
To calculate the empirical formula, we first calculate the percentage com[position of the individual elements.
Percentage composition of iridium = 16.7 / 27 * 100 = 61.85 %
Percentage composition of selenium = 10.3 / 27 * 100 = 38.15 %
Next is to divide the percentage composition of each element by their respective molecular masses
Molecular mass of iridium = 192 g/mol
Molecular mass of selenium = 79g/mol
Iridium = 61.85 / 192 = 0.3221
Selenium = 38.15 / 79 = 0.4829
Next is to divide the values by the smaller of the two values
Iridium = 0.3221 / 0.3221 = 1
Selenium = 0.4829 / 0.3221 = 1.5
Next is to round up the values to a whole number
Iridium = 1
Selenium = 2
The empirical formula therefore is Ir Se2
VSEPR theory predicts an identical shape for all of the following, except:_______. A. NH_3 B. H_3O^+ C. BH_3 D. CH_3^+ E. All of these choice same geometry.
Answer:
C. BH_3
Explanation:
The VSEPR is known as the valence shell electron pair repulsion theory. The VSEPR theory determines the total number of electron pairs (TEP) surrounding the central atom of a species. The TEP consists of the bond pairs (BP) and lone pairs (LP). In this model, all the electron pairs (like charges) will orient themselves in such a way as to minimize the electrostatic repulsion between them. These repulsions determine the geometry of the covalent bonds around the central atom.
In the options given, all the molecules have identical geometry except BH_3. This is as a result of the absence of a lone pair on the BH_3 compound.
A sprinter is running 200.0 m in 21.9s. What is the average speed of the sprinter in km per hour?
Answer:
Average speed = 333.3 km/hrExplanation:
The average speed of a body can be found by using the formula
[tex]Average \: \: speed = \frac{distance}{time} [/tex]
To find the average speed in km/h first convert the distance from m to km and the seconds from s to hr.
For the distance
2000 m
1000 m = 1 km
2000 m = 2000/1000 = 2 km
For the seconds
21.9 s
3600 s = 1 hr
21.9 s = 21.9/3600 = 0.006 hrs
Substitute the values into the above formula and solve for the Average speed
That's
[tex]Average \: \: speed = \frac{2}{0.006} [/tex]
We have the final answer as
Average speed = 333.3 km/hr
Hope this helps you
What are the properties of the aluminum in the
can? Check all that apply.
It conducts electricity well.
It is solid
It is brittle.
It does not react easily with water or air.
It is less dense than water.
Answer:
What are the properties of the aluminum in the can? Check all that apply.
*It conducts electricity well.
*It is solid.
It is brittle.
*It does not react easily with water or air.
It is less dense than water.
Explanation:
a b d
The properties of aluminium (Al) includes electrical conductivity, solid and it does not react easily with water. Therefore, option A, B and D are correct.
What is aluminium?Aluminium is a common metal we use day to day. It is an electropositive element and due to its metallic nature, Al shows electrical and thermal conductivity. Unlike other metals Al can withstand brittleness and it is ductile in nature.
Aluminium easily reacts with oxygen and forms an oxide layer on its surface so that, it can resist attack by other chemical such as acid or bases as well as oil and water. Hence water does not easily react with aluminium.
Therefore, we can say that aluminium is a solid which conduct electricity and not easily reacts with water.
To learn more about Al, refer the link below:https://brainly.com/question/23755698
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Yesinia read that certain perfume ingredients, called esters, would agitate bees. Because perfume formulas are secret, she decided to determine whether the unknown Ester X was present in four different perfumes by observing the bees’ behavior. She placed a saucer containing 10 mL of the first perfume 3 meters from the beehive. She recorded the time required for the bees to emerge and made observations on their behavior. After a 30-minute recover period, she tested the second, third and four perfumes. All experiments were conducted on the same day when the weather conditions were similar, that is, air temperature and wind. What was the hypothesis? What would be the control group? What is the experimental group? What was deliberately changed? What responded to the change?
Answer:
Hypothesis: IF the perfumes contained Ester "X", THEN the bees would be agitated
Control group: The control group would be the group of bees that did not receive any perfume treatment
Experimental group: Bees that were exposed to the different perfumes
Independent variable: The type of perfumes
Dependent variable: the behavior of the bees
Explanation:
An hypothesis is a testable explanation or suggested solution to a problem that is subject to testing (for proving or disproving) via experimentation. The hypothesis of this experiment will be: IF the perfumes contained Ester "X", THEN the bees would be agitated
The control group of an experiment is the group that does not receive the experimental treatment or the group whose independent variable is not changed. In this case, there is no stated control group but control group of this particular experiment could be the BEES THAT WERE NOT EXPOSED TO ANY PERFUME.
The experimental group, as opposed to the control group, is the group that receives experimental treatment. In this case, it is the group of bees that were exposed to the different types of perfumes.
In an experiment, the variable that is deliberately changed by the experimenter is called the independent variable. The independent variable in this question is the TYPE OF PERFUME given to the bees.
The variable that responds to the changes made to the independent variable is called the dependent variable. The dependent variable, which is the measured variable, is THE BEHAVIOR OF THE BEES.
Calculate the solubility of PbCO3 in water at 25 degree C.
Answer:
2.7 × 10⁻⁷ M
Explanation:
Step 1: Write the reaction for the solution of PbCO₃
PbCO₃(s) ⇄ Pb²⁺(aq) + CO₃²⁻(aq)
Step 2: Make an ICE chart
To relate the solubility of PbCO₃ (S) with its solubility product constant (Ksp) we will make an ICE chart.
PbCO₃(s) ⇄ Pb²⁺(aq) + CO₃²⁻(aq)
I 0 0
C +S +S
E S S
The solubility product constant is:
Ksp = 7.4 × 10⁻¹⁴ = [Pb²⁺] × [CO₃²⁻] = S²
S = √7.4 × 10⁻¹⁴ = 2.7 × 10⁻⁷ M
Light travels at roughly 3.00×108ms. What is this speed in miles per minute? Use 1mi=1609.344m and 60s=1min.
Answer:
1.12x10⁷ mi / min
Explanation:
Speed is a magnitude defined as the distance an object travels per unit of time.
Speed light is 3.00x10⁸ m/s. To convert this to miles per minute we need to convert the meters to miles and the seconds to minutes:
3.00x10⁸ m/s * (1mi / 1609.344m) = 186411.4 mi/s
186411.4 mi/s * (60s / 1min) =
1.12x10⁷ mi / minWhat are the laws of Newton?
Answer:
an object that is at rest will stay at rest inless a force acts upon it.
An oject that is in motion will not change its velocity unless a force acts upon it.
Answer:
First law
In an inertial frame of reference, an object either remains at rest or continues to move at a constant velocity, unless acted upon by a force.[2][3]
Second law
In an inertial frame of reference, the vector sum of the forces F on an object is equal to the mass m of that object multiplied by the acceleration a of the object: F = ma. (It is assumed here that the mass m is constant – see below.)
Third law
When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction on the first body.
help pls with chemistry question
Answer:
1×10⁸ Hz.
Explanation:
From the question given above, the following data were obtained:
Wavelength (λ) = 3 m
Frequency (f) =?
The wavelength of a wave and it's frequency are related by the following equation:
Velocity (v) = wavelength (λ) × frequency (f)
v = λf
With the above equation, we can obtain the frequency of the light wave as follow:
Wavelength (λ) = 3 m
Velocity (v) of light = 3×10⁸ m/s
Frequency (f) =?
v = λf
3×10⁸ = 3 × f
Divide both side by 3
f = 3×10⁸ / 3
f = 1×10⁸ Hz
Therefore, the frequency of the light wave is 1×10⁸ Hz
Hydrogen reacts with nitrogen monoxide to form dinitrogen monoxide (aughing gas) according to the equation: H2 (9) + 2 NOg) N20() + H20G) Based on the following data: H2 (M) NO (M) Rate (M*s) Trial 1 0.30 0.35 2.835 x 10-3 Trial 2 0.60 0.35 1.134 x 10-2 Trial 3 0.60 0.70 2.268 x 10-2 a. What is the order with respect to H2? b. What is the order with respect to NO? c. What is the rate equation for this reaction? d. Calculate the rate constant for the reaction.
Explanation:
H2 (9) + 2 NOg) N20() + H20G)
H2 (M) NO (M) Rate (M*s)
Trial 1 0.30 0.35 2.835 x 10-3
Trial 2 0.60 0.35 1.134 x 10-2
Trial 3 0.60 0.70 2.268 x 10-2
a. What is the order with respect to H2?
Comparing trials 1 and 2,the concentration of H is doubled and that leads to an increase in the rate of the reaction by a factor of 4. This means the order with respect to H is 2.
b. What is the order with respect to NO?
Comparing trials 2 and 3, the concentration of NO is doubled and that leads to an increase in the rate of the reaction by a factor of 2. This means the order with respect to NO is 1.
c. What is the rate equation for this reaction?
rate = k [H]²[NO]
d. Calculate the rate constant for the reaction.
Taking trial 1;
rate = k [H]²[NO]
2.835 x 10-3 = k (0.30)² (0.35)
k = 90 x 10-3 = 0.09 L2 mol-2 s-1
A children’s pain relief elixir contains 10.6 cg acetaminophen per 1 teaspoon. The dosage recommended for a child who weighs 34 lbs, is 1.5 teaspoons. What is the dosage of acetaminophen, expressed as mg acetaminophen/kg body weight, for a child weighing 34 lbs?(1 kg=2.205 lbs)
Answer:
Dosage of acetaminophen = 15.9 cg acetaminophen
Explanation:
Given:
1 teaspoon = 10.6 cg acetaminophen
Dosage to 34 lbs child = 34 lbs
Given dose = 1.5 teaspoon
Find:
Dosage of acetaminophen
Computation:
⇒ Dosage of acetaminophen = 1.5 teaspoon × [10.6 cg acetaminophen]
Dosage of acetaminophen = 15.9 cg acetaminophen
Rank the following bonds in order of decreasing bond length, based on periodic trends, starting with the longest bond at the top of the list.H-S H-I H-Se H-BI. H-I II. H-SeIII. H-BrIV. H-S
Answer:
H-BI,H-Se,H-S,H-I,H-Br
Explanation:
One thing that must be kept in mind is that atomic size increases down the group and decreases across the period. The bond lengths of species are influenced by the relative sizes of atoms or ions present in the bond.
The bonds in the answer have been arranged on basis of their decreasing atomic size because the greater the atomic size of the atoms, the greater the bond length and vice versa.
Classify each substance based on the intermolecular forces present in that substance.A. H2OB. CH4C. CO D. CH3Cl1. Hydrogen bonding, dipole dipole, and dispersion2. Dipole dipole and dispersion only 3. Dispersion only
Answer:
H2O - Hydrogen bonding, dipole dipole, and dispersion
CH4 - Dispersion only
CO - Dipole dipole and dispersion only
CH3Cl - Dipole dipole and dispersion only
Explanation:
Hydrogen bonding can only exist when hydrogen is bonded to a small highly electronegative atom such as oxygen hence hydrogen bonds, dipole interactions and dispersion by are present in water.
CH4 is a nonpolar molecule hence only dispersion forces are present.
CH3Cl and CO both possess dipoles in the molecule hence both dipole interactions and dispersion forces exist in the molecule.
Convert 2.350 km/hour to cm/sec HELP NOW PLEASE!!!! I NEED THE WORK
Answer:
1km/h =27.778cm/s
therefore
if 1km/h=27.778cm/s
2.350km/h=?
cross multiple
2.350km/h X27.778cm/s /1km/h
=65.2783cm/s
Select the correct answer.
Which phrase best describes heat?
O A. the energy that an object has as a result of its temperature
OB. the average translational kinetic energy of the particles in an object
ОС. the energy transferred between objects at different temperatures
OD
the total amount of energy possessed by the particles in an object
Answer:
C is the answer hope I helped you have a good day by
You found several studies related to the service provided by the company. Which data will you use to make an informed decision? Check all that apply.
data from a celebrity magazine
data verified by other studies
data provided by an ice cream manufacturer
data gathered once to show the reliability of the company
data from a report put out by a government agency
Answer: it’s b,c and e ,your welcome :) (just took the test on edge)
Answer:
B. data verified by other studies
C. data provided by an ice cream manufacturer
E. data from a report put out by a government agency
Explanation:
Place these hydrocarbons in order of decreasing boiling point. Rank from highest to lowest boiling point. 1. Paraffin, C40Hg2 2. Propane, G2H53. Hexane, C6H14 4. 2,2-dimethylbutane, C6 H14 5. Heptadecane, C17H36A. Highest BPB. Highest BP
Answer:
Paraffin > Heptadecane > Hexane > 2,2-dimethylbutane > Propane
Explanation:
It must first be establish that all the molecules listed in the question are alkanes. For alkanes, the intermolecular forces between the molecules of alkanes increases with increasing molecular weight. This is as a result of increase in the surface area of the molecule. Increase in surface area implies a greater degree of dispersion forces.
This is the reason why high boiling points are observed for high molecular weight alkanes.
Though alchemists were often superstitious, they left a rich legacy for modern chemists. What was their main contribution?
though alchemists were often superstitious, they left a rich legacy of modern chemists. what was their main contribution-
Explanation:
they were the first to preform experiments.