Answer:friction
Explanation:
What is the mass number of an
atom which contains 21 electrons,
21 protons, and 24 neutrons?
21
66
42
45
Answer:
66 i think
Explanation:
because i add 21+21+24=66
Select the appropriate shape for the given volume formula
Answer: Cylinder , Sphere , Rectangular prism , Cone
i did an online work
Classify each of the following values by the number of significant figures present in each. 8.314 J/mol-K 6.022x10 23 mol-1 12 mL 1.2 years 7.0 m2 50, cm 0,005 L 40.7 g 670.90 in 0.6258 mg 2.205 lb 3270 ft 90 m 5 significant 4 figuressignificant 3 figuressignificant 2 figuressignificant 1 figures
Answer:
5 significant figures: 670.90 in.
4 significant figures: 8.314 J/mol-K, 6.022x10 23 mol-1, 0.6258 mg, 2.205 lb and 3270 ft.
3 significant figures: 40.7 g.
2 significant figures: 12 mL, 1.2 years, 7.0 m2, 50, cm and 90 m.
1 significant figure: 0,005 L.
Explanation:
Hello,
In this case, we proceed as follows:
* 8.314 J/mol-K has 4 significant figures since 8, 3, 1 and 4 are significant (nonzero).
* 6.022x10 23 mol-1 has 4 significant figures since 6, 0, 2 and 2 are significant including the zero as it is at the right of the first nonzero digit (6).
* 12 mL has 2 significant figures since 1 and 2 are significant (nonzero).
* 1.2 years has 2 significant figures since 1 and 2 are significant (nonzero).
* 7.0 m2 has 2 significant figures since 1 and 2 are significant (nonzero).
* 50, cm has 2 significant figures since 1 and 2 are significant (nonzero).
* 0,005 L has 1 significant figure since 5 is the only nonzero digit.
* 40.7 g has 3 significant figures since 4, 0 and 7 are significant including the zero as it is at the right of the first nonzero digit (4).
* 670.90 in has 5 significant figures since 6, 7, 0, 9 and 0 are significant including the zeros as they are at the right of the first nonzero digit (6).
* 0.6258 mg has 4 significant figures since the first zero is at the left of the first nonzero digit, therefore, it is not included.
* 2.205 lb has 4 significant figures since 2, 2, 0 and 5 are significant including the zero as it is at the right of the first nonzero digit (2).
* 3270 ft has 4 significant figures since 3, 2, 7 and 0 are significant including the zero as it is at the right of the first nonzero digit (3).
* 90 m has 2 significant figures since 1 and 2 are significant (nonzero).
Regards.
A certain block is floating in water with 77% of itself submerged. It has a length of 4.3 cm, a width of 5.9 cm, and a height of
2.75 cm. What is its mass, in kilograms?
a. 1.86 kg
b. 2.77 kg
c. 0.0086 kg
d. 5.98 kg
e. 3.62 kg
f. 0.0537 kg
Answer:
f. 0.0537 kg
Explanation:
To solve this, we use the formula for force of buoyancy (Fb) = Vs × D × g
Where; Fb= Force of buoyancy
Vs= Volume of submerged
block
D= Density of water that block
submerges in
g= acceleration due to gravity
In this question, volume of block can be calculated using L×B×H
= 4.3cm × 5.9cm × 2.75cm = 69.7675cm^3
If 77% of the block is submerged in water, then 77/100 × 69.7675cm^3
= 53.72cm^3 is the Volume of submerged block
Density of water is known as 1000kg/m^3 while the gravitational force is 10m/s^2
We need to convert the Vs (volume of submerged block) to m^3 by dividing by 1,000,000
Hence, Vs = 53.72/1000000
Vs= 0.00005372m^3
Using the formula; (Fb) = Vs × D × g
Fb = 0.00005372m^3 × 1000kg/m^3 × 10m/s^2
Fb = 0.5372kg/m/s^2
Therefore, the force of buoyancy of the object on water is 0.5372kg/m/s^2
Recall that; Mass (m) = Volume (V) × Density (D)
Force of buoyancy (Fb) = Vs×D = mass (m) × acceleration due to gravity (g)
i.e. mass = Fb/g
= Mass of the block = 0.5372/10
Mass = 0.05372kg
Therefore, the mass of the block in kg is 0.05372kg
Scientists are studying different jackets made for extremely cold, snowy weather. They are trying to find jackets that
are warm but also thin enough to allow for natural bodily movement.
Which question could the scientists answer scientifically?
do
O Which jacket's color looks the best?
O Which jacket traps the most heat?
O Would warm and thin jackets cost less?
Which jacket seems the most professional?
Please anybody can ya help me I have this on my test and if I fail I don’t pass this class
Element A has 15 protons. Determine the number of neutrons in its isotope with mass number 33
Answer:
18 i think
Explanation:
Explain why each molecule has a higher vapor pressure at a given temperature than the other in the pair. Match the words in the left column to the appropriate blanks in the sentences on the right. a. does not exhibit dispersion forces b. does not exhibit dipole-dipole forcescc. is polar d. has a smaller molar mass e. does not exhibit hydrogen bonding . 1. The main reasons why CH4 has a higher vapor pressure at a given temperature when compared to CH3Cl is that CH4____and_____. 2. The main reasons why H2CO has a higher vapor pressure at a given temperature when compared to CH3OH is that H2CO_____and_____.3. The main reason why CH3OH has a higher vapor pressure at a given temperature when compared to CH3CH2CH2OH is that CH3OH_____.
Complete Question
The complete question is shown on the first image
Answer:
1 The main reasons why CH4 has a higher vapor pressure at a given temperature when compared to CH3Cl is that CH4 has a smaller molar mass and does not exhibit dipole to dipole force .
2. The main reasons why H2CO has a higher vapor pressure at a given temperature when compared to CH3OH is that H2CO has a smaller molar mass and does not exhibit hydrogen bonding
3. The main reason why CH3OH has a higher vapor pressure at a given temperature when compared to CH3CH2CH2OH is that CH3OH has a smaller molar mass
Explanation:
The higher vapor pressure of the molecules at the given temperature has been based on the molar mass and the binding between the atoms of molecules.
1. The main reasons why [tex]\rm CH_4[/tex] has a higher vapor pressure at a given temperature when compared to [tex]\rm CH_3Cl[/tex] is that [tex]\rm CH_4[/tex]:
Has a smaller molar mass, and Does not exhibit dipole-dipole forcesThus options b and c are correct.
2. The main reason why [tex]\rm H_2CO[/tex] has a higher vapor pressure at a given temperature when compared to [tex]\rm CH_3OH[/tex] is that [tex]\rm H_2CO[/tex]:
Has a smaller molar mass, and Does not exhibit hydrogen bondingThus options c and e are correct.
3. The main reason why [tex]\rm CH_3OH[/tex] has a higher vapor pressure at a given temperature when compared to [tex]\rm CH_3CH_2CH_2OH[/tex] is that [tex]\rm CH_3OH[/tex]:
Has a smaller molar mass.Thus Option c is correct.
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Which of these relationships is true of an uncharged atom?
A) The atomic mass is equal to the atomic number.
B) The number of electrons is equal to the number of neutrons.
C) The number of protons is equal to the number of electrons.
D) The atomic mass is equal to the number of electrons.
Answer:
The correct option is C) The number of protons is equal to the number of electrons.
Explanation:
Atoms are made up of particles called protons, neutrons, and electrons. Protons and neutrons are in the center of the atom and form the nucleus, while electrons surround the nucleus. Electrons have a negative charge. The charge of the protons is positive and finally, the neutrons have no charge.
If the atom has no charge, this means that the total charge of the atomic nucleus, which is positive due to the presence of the protons, is equal to the negative charge of the electrons, so that it cancels out.
So, the correct option is C) The number of protons is equal to the number of electrons.
The atomic number can tell us how many neutrons are in an atom. Question 4 options: True False
Answer:
true i think
Explanation:
Is melting sugar a chemical or physical change? Please provide an explanation
Answer:
Hola Amigo! Here's Ur Answer :D
Explanation:
The chemical reaction we are most familiar with is that of melting: sugar decomposes at a temperature ranging between 184 and 186°C. This is a very recent discovery we owe to a team of researchers in Illinois. Basically, when we heat sucrose gently, this produces a phenomenon known as “ apparent melting ”.
Happy to Help! :D
Answer:
physical change is what the answer above is saying for anybody who is confused
Explanation:
a physical change has to do with appearance while chemical change has to do with composition. melting the sugar does not change the fact its just sugar therefore not changing the composition.
HOPE THIS HELPS!!! :)
<333333333333
How many mL are equal to .0024 L?
Answer:
1
Explanation:
1000ml=1l
? =0.0024l
0.0024/1000×1
0.0000024ml
Volume has been the amount of space covered and occupied by the substance. The volume of the substance has 0.0024 liters is equivalent to 2.4 milliliters.
What is volume?Volume has been defined as the three-dimensional space that has been occupied by the substance in space. It has been measured in derived units of length like cubic meter (m³), cubic centimeter (cm³), liter (l), and milliliter (ml).
The units of the volume can be converted into various derived units by multiplication and division of the units. The small units are derived from larger ones by multiplying and larger units are converted into smaller ones by division.
Given,
Volume = 0.0024 L
Converting units as:
1 liter = 1000 mL
0.0024 L = 2.4 mL
Therefore, the volume is 2.4 milliliters.
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Find the density of a moving box that weighs 898 grams and has a volume of 300 cm3.
Answer:
d ≈ 3 g/cm³
Explanation:
Density Formula: d = m/v
Step 1: Define variables
mass m = 898 grams
volume v = 300 cm³
Step 2: Substitute and evaluate
d = 898 g/300 cm³
d = 2.99333 g/cm³
d ≈ 3 g/cm³ (1 sig fig)
plants are unable to move to a new location in response to changes in their environment. Which organelle plays a role in maintaining homeostasis in a plant?
Answer:
Plants are unable to move to a new location in response to changes in their environment. Which of the following organelles plays a role in maintaining homeostasis in a plant? a. Cell Wall b. Chloroplast c. Vacuole d. Nucleus ____ 6. In the diagram below, Cell I and II represent typical cells. In both cells,
Explanation:
:P
Answer:
Vacuole
Explanation:
did it!
Classify the organic compounds by the class of their functional group. Drag the appropriate items to their respective bins.CH3COCH2CH2CH2CH3 CH3CH2COOH CH3CH2CH2CHO CH3CH2CH2NH2 Carboxylic acid Amine Ketone Aldehyde Alcohol
Answer:
Explanation:
CH₃COCH₂CH₂CH₂CH₃ ------- Ketone because it contains C = O group .
CH₃COH=CHCH₂CH₂CH₃ ------ Alcohol group because it contains - OH group .
CH₃CH₂COOH ---- Carboxylic group because it contains - COOH group.
CH₃CH₂CH₂CHO ------- Aldehyde group because it contains - CHO group
CH₃CH₂CH₂NH₂ ----- Amine group because it contains - NH₂ group .
The compounds can be categorized as, Carboxylic acid: [tex]\rm CH_3CH_2COOH[/tex]; Amine: [tex]\rm CH_3CH_2CH_2NH_2[/tex]; Ketone: [tex]\rm CH_3COCH_2CH_2CH_2CH_3[/tex]; Aldehyde: [tex]\rm CH_3CH_2CH_2CHO[/tex], and Alcohol: [tex]\rm CH_2COH=CHCH_2CH_2CH_3[/tex].
Organic compounds are the hydrocarbons that has been divided based on the functional groups. The compounds that fall into the following category are:
Carboxylic acid: These are compounds with the presence of carboxylic group -COOH. The carboxylic compound has been [tex]\rm CH_3CH_2COOH[/tex].Amine: These are compounds with the presence of amine group -[tex]\rm NH_2[/tex]. The amine compound has been [tex]\rm CH_3CH_2CH_2NH_2[/tex].Ketone: These are compounds with the presence of ketone group -C=O. The ketone compound has been [tex]\rm CH_3COCH_2CH_2CH_2CH_3[/tex].Aldehyde: These are compounds with the presence of aldehyde group -CHO. The aldehyde compound has been [tex]\rm CH_3CH_2CH_2CHO[/tex].Alcohol: These are compounds with the presence of hydroxyl group -OH. The alcohol compound has been [tex]\rm CH_2COH=CHCH_2CH_2CH_3[/tex].The compounds can be categorized as, Carboxylic acid: [tex]\rm CH_3CH_2COOH[/tex]; Amine: [tex]\rm CH_3CH_2CH_2NH_2[/tex]; Ketone: [tex]\rm CH_3COCH_2CH_2CH_2CH_3[/tex]; Aldehyde: [tex]\rm CH_3CH_2CH_2CHO[/tex], and Alcohol: [tex]\rm CH_2COH=CHCH_2CH_2CH_3[/tex].
For more information about organic compounds, refer to the link:
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Question 3(Multiple Choice Worth 3 points)
(01.02 LC)
What is the metric unit for mass?
O Meters
O Kilograms
O Pounds
O Matter
Answer:
kilograms
Explanation:
Answer:B) Kilograms
Explanation:I took the test and got it right!
An object has a density of 16.3 g/mL and a volume of 0.46 L. Calculate the
mass of the object in pounds.
Answer:
The answer is
16.50 IbsExplanation:
To find the mass of a substance given the density and volume we use the formula
mass = Density × volumeFrom the question
Density = 16.3 g/mL
volume = 0.46 L
We must first convert the volume from L to mL
If 1 L = 1000 mL
Then 0.46 L = 0.46 × 1000 = 460 mL
Substitute the values into the above formula and solve
That's
mass = 16.3 × 460 = 7498 g
To convert the mass from g to lbs we use the conversion
1g = 0.0022 Ibs
If 1 g = 0.0022 Ibs
Then 7498 g = 7498 × 0.0022
We have the final answer as
16.50 IbsHope this helps you
Convert the following:.0995Kg=.
g
Answer:
995
Explanation:
1kg = 1000g
lalalalalalalalalalalalallalalalalalalalalalalalalalalalalalalala
Answer:
995kg = 995000g
Explanation:
1 kg = 1000 g
Convert 75 mL of water to gallons (show work)
Answer:
[tex]\huge\boxed{\sf 75\ mL = 0.02\ gallons}[/tex]
Explanation:
1 mL = 0.000264 gallons
Multiplying both sides by 75
75 mL = 0.000264 * 75 gallons
75 mL = 0.02 gallonsHow many atoms are in 6.30 moles of selenium (Se)?
x 10
atoms
Answer:
3.79 e+24
Explanation:
1 mol = 6.022*10^24 atoms
6.30 * ×[tex]\frac{6.022*10^2^3atoms}{1mol}[/tex] = 3.79386*10^24
The answer must have 3 sig figs
How are sheep used as a symbol in the alchemist book?
Explanation:
Santiago's sheep in the novel alchemist symbolize, the sheep symbolize the ideals of modesty, simplicity and self-actualization in their peaceful yet fulfilled lives. ... Santiago also learns the lessons of life by watching his flock, and later these lessons are enhanced when he explores the desert and hears his inner voice.
Which of the following options is correct?
All of the following are chemically modified carbohydrates except
a. galactosamine.
b. cellulose.
c. glucosamine.
d. chitin.
e. glucuronic acid.
Answer:
b. cellulose.
Explanation:
Cellulose is a polysaccharide consisting of a long chain of repeating glucose units (i.e., β-D-glucose units) that produce long unbranched chains. Cellulose can be considered as a natural polymer (i.e., a non-modified carbohydrate) because it is composed of repeated chains of β-D-glucose molecules stuck together. The cellulose polysaccharide is a principal component of plant cell walls.
An ibuprofen suspension for infants contains 100 mg/5.0 mL suspension. The recommended dose is 10 mg/kg body weight. How many mL of this suspension should be given to an infant weighing 18 lb?
Answer:
32,8mL
Explanation:
1lb=2.2kg
18lb= 8.2 kg
100mg/5mL=20mg/1mL
164mg=32.8mL
In the metric system, the ________ describes the relationship of each unit to the base unit.
a. suffixb. none of the answer choices are correct.c. synonymd. punctuatione. prefix
Answer:
prefix
Explanation:
In a metric system the prefix shows the relationship of each unit to the base unit.
The metric system is an international system of measurement that uses base units of meter for measuring distance, liter for measuring volume and grams for measuring mass.
The metric unit can be smaller or bigger than the base unit, hence, when using the metric system, the prefix shows the relationship between each unit to the base unit.
Thus, we can conclude that the prefix shows the relationship of each unit to the base unit.
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pls explain how the energy of a marble is transformed as it rolls down a ramp.
Answer:
Energy is not created but transformed meaning the energy just transformed into a different type meaning at all points of the ramp the energy stays the same because all of its energy is just transformed into kinetic energy.
Explanation:
Which of the following statements is a true statement concerning a reaction that has reached a state of equilibrium?
a. A system has reached equilibrium when there are equal amounts of products and reactants present in the system.
b. A system has reached equilibrium when the rate constant for the forward reaction equals the rate constant of the reverse reaction.
c. A system has reached equilibrium when the reaction has stopped and no more products are formed.
d. A system has reached equilibrium when the concentrations of reactants and products remain constant.
Answer: A system has reached equilibrium when the concentrations of reactants and products remain constant.
Explanation:
The reactions which do not go on completion and in which the reactant forms product and the products goes back to the reactants simultaneously are known as equilibrium reactions.
The equilibrium is dynamic in nature and the reactions are continuous in nature. Rate of forward reaction is equal to the rate of backward reaction.
Equilibrium state is the state when reactants and products are present but the concentrations does not change with time, that is the concentration remains constant.
What is the mass of a 67 dL sample of a salt solution?
Answer:
6733.5 g of NaCl
Explanation:
We can assume that the salt solution is a saline solution which contains NaCl in water at 0.90%, whose density is 1.005 g/ml.
So we need to apply the density concept to solve the question.
Density = mass / volume
We convert dL to mL → 67 dL . 100mL / 1 dL = 6700 mL
Density = mass / volume
Volume . Density = mass
6700 mL . 1.005 g = 6733.5 g of NaCl
From the list of substances, identify each as a strong acid, strong base, or neither a strong acid nor a strong baseDrag the appropriate items to their respective bins. Strong acid Strong base Neither a strong acid nor a strong baseHNO3 HCl NaCl Ca(OH)2 CH3COOH CH3NH2 CH3OH HF RbOH
Answer:
Answer is in the explanation
Explanation:
All acids that dissociates completely in water are considered strong acids. In the same way, bases that dissociates completely in water are strong bases. All hydroxides made from alkali metals and heavier alkali earth metals are strong bases.
HNO3 dissociates completely in water: STRONG ACID.
HCl dissociates completely in water. STRONG ACID.
NaCl is a salt. Neither a strong acid nor a strong base.
Ca(OH)2. Heavy alkaline earth metal. STRONG BASE.
CH3COOH an acid that doesn't dissociate completely in water. Neither a strong acid nor a strong base.
CH3NH2 is a weak base that doesn't dissociate completely in water. Neither a strong acid nor a strong base.
CH3OH. Methanol is an alcohol. Neither a strong acid nor a strong base.
HF is a weak acid; doesn't dissociate completely in water. Neither a strong acid nor a strong base.
RbOH. Is an hydroxide made from alkali metal. STRONG BASE.
what was the physical property used by mendleev in creating his periodic table.
Answer:
melting point and boiling point
PLS HELP!!
Nitric acid is made by a sequence of reactions, shown below.
4NH3(g) +5O2(g) = 4NO(g) + 6H2O(g)
2NO(g) + O2(g) = 2NO2(g)
3NO2(g) + H2O(g) = 2HNO3(g)+ NO(g)
If the first reaction occurs with 96.2% yield, the second reaction occurs with a 91.3% yield and the third reaction proceeds with a 91.4% yield,
calculate the following:
(a) The grams of nitric acid produced from 1216 grams of ammonia.
(b) The percent yield for the overall process
Answer:
from the 1st equation:
4NH3 4NO
4 *(68) 4*30
1216 X mass of NO = 536.5 g
from the 2nd Equation
2NO 2NO2
2*30 2* 46
536.5 x mass of NO2 = 822.6 grams
from the 3rd Equation
3NO2 2HNO3
3*(46) 2* (63)
822.6 X mass of nitric acid = 751.06 gram
b) % yields = ( 96.2%* 91.3% *91.4%)= 80.3%
What is the purpose of a salt bridge in an electrochemical cell?
Answer:
A salt bridge, in electrochemistry, is a laboratory device used to connect the oxidation and reduction half-cells of a galvanic cell (voltaic cell), a type of electrochemical cell. It maintains electrical neutrality within the internal circuit, preventing the cell from rapidly running its reaction to equilibrium.