Answer:A
Explanation:
Calculate the answers to the appropriate number of significant numbers
32.567
135.0
+ 1.4567
—————
Answer:
32.567+135.0+1.4567=169.027
to significant figures is 16
As the mass of a sample increases, the number of moles present in the sample
Answer:
increases
Explanation:
Answer: will also increase
Explanation:
If the mass in a sample increases, the number of molecules will also increase. Hope this helps!
Why the bromine and air can mix together?
A. Bromine is denser than air
B. Bromine is lighter than air
C. Bromine molecules moved upwards and molecules in air moved downwards
D. Molecules in bromine and air moved randomly
Chooses the correct statement from the above
Answer:
D. Molecules in bromine and air moved randomly
Explanation:
The molecules of both bromine and air are in the gas phase.
Since the molecules of gases are far apart and moving randomly, the bromine and air molecules can easily mix together.
A is partially correct. bromine is denser than air, but that doesn't explain why they mix.
B is wrong. Bromine is denser than air.
C is partially correct. The molecules of bromine and air moved upwards and downwards, but the also moved randomly in many other directions.
each electron in an atom has a charge of -1 and each proton has a charge of 1. what is the overall charge of atom that contains 2 electron and 2 proton
Answer:
0
Explanation:
Positive Change of 2 cancels the negative charge of 2
To see the number of atoms of an element in a given molecule we need to multiply stoichiometry to the number that is written on the foot of the element that is stoichiometry. Therefore, the overall charge of atom that contains 2 electron and 2 proton is zero.
What is atom?Atom is the smallest particle of any element, molecule or compound. Atom can not be further divided. Atoms contains nucleus in its center and electron that revolve around the atom in fixed orbit.
In the nucleus, proton and neutron are present. Electron has -1 charge while proton has +1 charge. Neutron is neutral that is it has no charge. So overall the charge of nucleus is due to only proton, not by neutron. The overall charge of atom that contains 2 electron and 2 proton is zero.
Therefore, the overall charge of atom that contains 2 electron and 2 proton is zero.
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3 Select the correct answer. Which unit can be used to express the rate of a reaction? A. mL / s B. mL / g C. g / mL D. mL / mol E. s / mL Reset Next
Answer:
A) mL / s
Explanation:
What gas makes up 73% of earth's atmosphere?
Answer: nitrogen
Explanation:
A copper cylinder, 12.0 cm in radius, is 44.9 cm long. If the density of copper is 8.90 g/cm^3, calculate the mass in grans of the cylinder. (Assume pi=3.14
Answer:
we use: V = pi*(r^2)*h
V = 3.14*(12.0cm^2)*44.0 cm
V = 19895.04 cm^3
Therefore, mass = (8.90g/cm^3) * (19895.04 cm^3) = 177065.856 g
Explanation:
A copper cylinder, 12.0 cm in radius, is 44.9 cm long. If the density of copper is 8.90 g/cm^3, the mass of the cylinder is 180687.62g
What is density?Density is defined as the degree to which a material is packed together.
It is also defined as the measurement of the relative "heaviness" of objects with a fixed volume.
It is mass per unit volume.
Volume = ∧r²h
Volume = 3.14 x 12² x 44.9
= 20301.98 cm³
Density = mass / volume
So, mass = density x volume
= 8.90 g/cm³ x 20301.98
= 180687.62 g
Thus, a copper cylinder, 12.0 cm in radius, is 44.9 cm long. If the density of copper is 8.90 g/cm^3, the mass of the cylinder is 180687.62g.
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What is the MSDS? Why is it important? *
Answer:
Hey there!
A MSDS is a Material Safety Data Sheet, and can be used to provide detailed and comprehensive information about the hazards of a certain product, such as medicine or chemicals.
Let me know if this helps :)
How many sig figs does the answer to the following calculation have?
1.90 + 2.3 +5.700 = ?*
Answer:
The answer is 2 significant figures.
1.90+2.3+5.700=9.9
Which of the following equations best describes the energy at point C.
assuming energy is conserved?
OA. PEA = KEC
O B. PEA = KEc+PEC
OC. PER = KEc+ PEC
OD. PEB = PEC
Answer:
B. PEA = KEC. +PEC
Explanation:
From the figure it is clear that there is interconversion between potential energy ( PE ) and kinetic energy ( KE ) , so that total mechanical energy is conserved .
At A only potential energy exists . Kinetic energy is zero .
At B only kinetic energy exists . Potential energy is zero .
At C both potential and kinetic energy exist .
So Potential energy at A is equal to potential energy at C and kinetic energy at C
Ie , PEA = KEC + PEC .
Option B is correct .
can you pls tell me the word equations for all these equations
Answer:
Below
Explanation:
Balanced form;
[tex]2C_6H_6 +15O_2 -> 12CO_2+6H_2O\\\\ Ca_3(PO_4)_2 +8C -> Ca_3P_2 +8CO\\\\2HNO_2+O_2 -> 2HNO_3\\\\Ca(OH)_2 + CO_2 -> CaC0_3+H_2O\\\\2K +Br_2 ->2KBr\\\\2NaOH+FeSO_4 -. Na_2SO_4 +Fe(OH)_2[/tex]
1.Benzene + Dioxygen = Carbon Dioxide + Water
2.Tricalcium phosphate +Carbon = Calcium phosphide + carbon monoxide
3.Nitrous acid react with oxygen to produce nitric acid.
4.This means that the carbon dioxide and limewater react to produce calcium carbonate and water.
5.Potassium react with bromine to produce potassium bromide
6. An aqueous solution of ferrous sulphate reacts with aqueous solution of sodium hydroxide to form a precipitate of ferrous hydroxide and sodium sulphate remains in the solution.
What is the natural phenomenon that moves the
cough droplets through the air?
Answer:
For a mild human cough in air at 20 °C and 50% relative humidity, we found that ... larger droplets are dispersed into smaller ones gradually while moving away from the ... Complex phase change and transport phenomena such as evaporation and ... Natural Ventilation for Infection Control in Health-Care Settings
Explanation
Sugar when dissolved into water, propose whether the compound forms atoms, molecules or lattices. Justify you answer
Answer:
atoms
Explanation:
for sugar to dissolve in water hydaration must be equal to or greater than the lattice energy or molecular forces so when the molecular forces breaks new atoms are formed for recombination in new compound
12 Calculate An object has a mass of 77 kg and
an acceleration of 2.3 m/s2. Use the equation
F=
= ma to calculate the net force acting on the
object. Show your work.
Answer:
F=ma.
mass=77, acceleration=2.3.
77×2.3=177.1Newton
water has density of 1.0 g/L. What volume of water has mass 250 g?
Answer:
Examine the units: If the density is 1 g/mL, how many mL do you need to make 250 g?
X mL * 1 g/mL = 250 g
Solve for X
x mL = 250 g / 1 g/mL = 250 mL
Hope this helps :)
The volume of water = 250 L
The formula for density:
[tex]density = \frac{mass}{volume}[/tex]
Given, density = 1.0 g/L = 0.001 kg/L
mass = 250 g = 0.25 kg
Putting the values in the equation
[tex]0.001 = \frac{0.25}{volume}[/tex]
[tex]volume = \frac{0.25}{0.001}[/tex]
[tex]volume = 250 L[/tex]
Hence, the volume of the water is 250 L.
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Frank has a sample of steel that weighs 80 grams. If the density of his sample of steel is 8 g/cm3, what is the sample’s volume? The sample’s volume is cm3.
Answer:
The volume of the steel is 10cm3
Explanation:
Density is defined as the mass contained per unit volume.
Density= Mass
volume
Given : Mass of steel = 80 grams
Density of steel = 8g/cm3
Putting in the values we get:
8g/cm3 = 80g
Volume
Volume=80/8
=10
Thus the volume of steel is 10cm3
Density is an intensive property as it does not depend on the quantity of the substances Whereas mass and volume are extensive property. Therefore, the volume of sample of steel is 10cm³ if the density of his sample of steel is 8 g/cm³.
What is density?Density tells about the compactness of the substances, how much dense is the substances in other words. Object that is more denser than water they just sink in the water.
Mathematically, the formula for density can be given as
Density = Mass of the metal ÷volume marked on the graduated cylinder
Mass of steel = 80 grams
Density of steel = 8g/cm³
substituting all the given values in the above equation, we get
Volume of steel=80/8
On calculations, we get
Volume of steel =10cm³
Therefore, the volume of sample of steel is 10cm³.
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chemical synthesis of drugs allowed development of cancer treatments that save lives
Answer:yes
Explanation:
You are attempting to determine the thermodynamic properties of an unknown compound. You’ve already determined delta H fusion to be 5.56 kJ/mol and delta H vaporization to be 21.99 kJ/mol. In one of these previous experiments, 2.56 g of this compound was placed in a glass bulb and vaporized by placing the glass bulb into 200. g of hot water initially at 68.25 degrees Celsius, which resulted in a final water temperature of 67.91 degrees Celsius. You are now attempting to determine the enthalpy of solution of this compound. To this end, you dissolve 55.6 g of this compound in 495 g of water initially at 25.2 degrees Celsius. The final temperature of the solution is 19.4 degrees Celsius. What is the enthalpy of solution of this compound in kJ/mol?
Answer:
The heat of solution of the compound = 42.75 kJ/mol
Explanation:
Here we have;
The heat of vaporization = 21.99 kJ/mol
2.56 g of the compound is then placed in 200 g. of water
The temperature of the water reduces from 68.25°C to 67.91°C
The specific heat capacity of water = 4.19 kJ/kg = 4.19 J/g
Mass of the water = 200 g
Heat lost by the water ΔH = m × c × Δθ = n × ΔH vaporization of the compound
Where;
m = The mass of the water = 200 g
c = The specific heat capacity of water = 4.19 kJ/kg = 4.19 J/g
Δθ = The change in temperature = 68.25°C - 67.91°C = 0.34°C
n = The number of moles of the compound
ΔH = m × c × Δθ = 200×4.19×0.34 = 284.92 J = 0.28492 kJ
∴ n × ΔH vaporization of the compound = 0.28492 kJ
n = 0.28492 kJ/( ΔH vaporization of the compound) = 0.28492/21.99≈0.013 moles
∴ 2.56 g = 0.013 moles
1 mole = The molar mass of the compound = 2.56/0.013= 197.6 g/mol
Therefore;
The number of moles in 55.6 g of the compound = 55.6/197.6 = 0.2814 moles
The heat given by the water = ΔH = 495 × (25.2 - 19.4) × 4.19 = 12029.49 J
Therefore;
0.2814 × ΔH(solution) = 12029.49 J = 12.02949 kJ
ΔH(solution) = 12.02949/0.2814 = 42.75 kJ/mol
The heat of solution of the compound = 42.75 kJ/mol.
5) What is the empirical formula of a compound containing 47.37% carbon, 10.59% hydrogen, and 42.04% oxygen?
Answer:
C2H4O
two atoms of carbon four atoms of hydrogen and one atom of oxygen
25,000cg is equal to _g
Answer:
250 g
Explanation:
HELP! What is a pure substance salt or seawater???? PLEASE HELP ME!
Answer:
Your answer is salt. Pure substances are made of materials with one type of molecule. Seawater has salt and water molecules, which is more than one, so your answer is salt.
Hope this helps!
Answer in the correct significant figures: 9.66 / 0.33
Ethylene glycol (C2H6O2) is used as an antifreeze in cars. If 400 g of ethylene glycol is added to 4.00 kg of water, what is the molality? Calculate how much the freezing point of water will be lowered. The freezing-point depression constant for water is Kf = –1.86°C/m.
Answer:
The freezing point of water will be lowered 3°C
Explanation:
Remember that molality is generally the standard for calculating the concentration, between molarity and molality. In this question we have to apply molality, given the units as moles and kilograms.
We can start by receiving the molality of this solution through the following formula...
[tex]\mathrm{m}=\mathrm{(mass}\mathrm{/molar\:mass)} * (1000/\mathrm{mass\:of\:solvent)},[/tex]
[tex]\mathrm{m} =\mathrm{(400.0 g / 62.07 g/mol) * (1000 / 4000.0 g)},[/tex]
[tex]\mathrm{m} = (400/62.07) * (1000 / 4000) = \left(\frac{400}{62.07}\right)\left(\frac{1000}{4000}\right) = \frac{1000}{620.7} = 1.61108\dots\mathrm{m}[/tex]
Now we can determine how much the freezing point of water will be lowered, given that the freezing-point depression constant for water is Kf= –1.86°C/m. Remember that " Kf " is the final temperature, so to determine how much the temperature of the water will decrease, we can note the change in temperature...
[tex]\mathrm{change\:in\:temperature} = ( - 1.86\mathrm{C/m})(1.61\mathrm{m}) = - 1.86 * 1.61 = -2.9946[/tex]
[tex]-2.9946 = \mathrm{About\:-3C}[/tex]
Hence the freezing point of water will be lowered 3°C.
What is the shape of s-subshell?
Thus, the s subshell may contain only one orbital and the p subshell may contain three orbitals. Each orbital has its own distinct shape. An s orbital found in a s subshell is spherical, p orbitals found in p subshells are two-lobed, and d orbitals found in d subshells are four-lobed.
Answer:
The s-subshell may contain only one orbit and the p-subshell may contain three orbits . Each orbit has it own distinct shape
May this helps you
23. A certain sample of nitrogen gas consists of 9.26 1022 nitrogen atoms.
(a) How many moles of N atoms are present in this sample ?
(b) If the gas is entirely in molecular form, how many molecules are present in this
sample?
(c) What is the mass of the sample in gramme?
Answer:
a) 0.154 moles of N2
b) 9.27 × 10^22 molecules
c) 4.312 g
Explanation:
a)
1 mole of N2 contains 6.02 × 10^23 atoms
x moles of N2 contains 9.26 × 10^22 atoms
x= 9.26 ×10^22/6.02 × 10^23
x= 1.54 ×10^-1
x= 0.154 moles of N2
b)
1 mole of N2 contains 6.02 × 10^23 molecules
0.154 moles of N2 contains 0.154 moles × 6.02 × 10^23 = 9.27 × 10^22 molecules
c)
Molar mass of the nitrogen gas= 28 gmol^-1
Number of moles of nitrogen gas = 0.154 moles
Number of moles = mass/molar mass
0.154 moles= mass/28 gmol^-1
Mass= 0.154 moles × 28gmol^-1
Mass= 4.312 g
Which statement regarding serum magnesium (Mg ++) is true? (Select all that apply.) Alcohol-related diseases frequently cause low Mg+ levels. Vomiting is not generally seen as a major cause of Mg+ loss. Mg++ levels present similarly to calcium (Ca++) levels in the blood. Mg+ deficiencies often result in low serum potassium (K+) levels. Mg+ deficiencies must be treated before potassium (K+) deficiencies.
Answer:
-
Alcohol-related diseases frequently cause low Mg+ levels.
- Mg+ deficiencies must be treated before potassium (K+) deficiencies.
- Mg+ deficiencies often result in low serum potassium (K+)
- Mg++ levels present similarly to calcium (Ca++) levels in the blood.
- Vomiting is not generally seen as a major cause of Mg+ loss
What is the formal thought process of science?
Answer:
In science, you are looking for something and you discovered something else. This leads to many discovery among the world.
explain formation of covalent bonds when atoms share electrons.
Answer:
Covalent bonding occurs when pairs of electrons are shared by atoms. Atoms will covalently bond with other atoms in order to gain more stability, which is gained by forming a full electron shell. By sharing their outer most (valence) electrons, atoms can fill up their outer electron shell and gain stability.
Explanation:
true or false .Heat is the movement of thermal energy from one place to another.
Answer:
true.................
Answer:
Thermal energy that is transferred from one substance to another,moves from warmer to cooler objects. So True.
Explanation:
Which of the following BEST states the Law of Conservation of Matter?
Your answer:
B. The total mass of the reactants in a reaction is double the total mass of the product(s).
C. The total mass of the reactants in a reaction is less than the total mass of the product(s).
D. The total mass of the reactants in a reaction is greater than the total mass of the product(s).
Answer: there is not any correct answer but the law of conservation of matter states that the sum of the mass of the reactants should be equal to that of the product