Answer:
90 Minutes
Explanation:
Original concentration = 120 mg
Half life = 30 minutes
Minimum level = 15 mg
Basically, we are to calculate the time it would take to drop from 120 mg to 15 mg.
The half life of a substance is the time it takes for the original concentration of a substance to drop to half it's starting concentration.
First Half life:
Starting concentration = 120mg
Concentration after half life = 120 / 2 = 60 mg
Second Half life;
Starting concentration = 60 mg
Concentration after half life = 60 / 2 = 30 mg
Third Half life;
Starting concentration = 30 mg
Concentration after half life = 30 / 2 = 15 mg
We have reached the minimum 15 mg level. This means it took three half lives to get there.
Total time taken = No of Half lives * Half life duration = 3 * 30 mins = 90 Minutes
4 Explain why some acids are safe to consume
while others are not.
Answer:
Household cleaners, antiseptics and battery juice are examples of toxic chemicals that you cannot consume because they have high acids concentrations. However some are very healthy such as critic acids found in oranges. :) Hope this helped.
The way Earth's rotation makes winds curve.
Answer:
it is called the prevailing westerlies
Explanation:
How many grams of KClO3 will dissolve in 300g of water at 50°C?
Answer:
50 g
Explanation:
Please brainiest
The radius of a basketball hoop is 9 inches. Which expression can be used to find the
hoop's circumference in inches?
Answer:
2 [tex]\pi[/tex] r
Explanation:
Given that:
Radius of basketball = 9inches
Unknown:
Hoop's circumference = ?
Solution:
To solve this problem, we use the formula for the circumference of a circle.
The shape of the hoops is circular.
Circumference of a circle = 2 [tex]\pi[/tex] r
R is the radius of the basketball hoop
how many atoms are in 2.45 moles of hydrogen
Answer:
There are 1.4754246675000002e+24 atoms of Hydrogen within the measurement of 2.45 moles of hydrogen!
Explanation:
How many moles are 21.67 L of NH4CI?
Type your answer...
Answer:
0.967mole
Explanation:
Given parameters:
Volume of NH₄Cl = 21.67L
Unknown:
Number of moles = ?
Solution:
We assume that the volume was taken at standard temperature and pressure,
Then;
Number of moles = [tex]\frac{volume }{22.4L}[/tex]
Number of moles = [tex]\frac{21.67}{22.4}[/tex] = 0.967mole
An atom contains 8 protons, 8 neutrons and 8 electrons. A second atom contains
8 protons, 10 neutrons and 10 electrons. What can be said about these two
atoms?
A. Both atoms are neutral
B. The atoms are isotopes of each other
C. Both atoms are ions
D. These atoms cannot exist in nature
Answer:
B. Isotopes mean having differing number of neutrons but having the same amount of protons basically.
Explanation:
B. The atoms are isotopes of each other
Further explanationGiven
The first atom : 8 protons, 8 neutrons and 8 electrons
The second atom : 8 protons, 10 neutrons and 10 electrons
Required
Comparison
Solution
A. Atom is said to be neutral if the number of protons and electrons is the same
The first atom neutral
The second atom - anion : charge = -2(10 electron-8 proton)
B. isotopes = the same atomic number and different mass number
The first atom : atomic number = 8, mass number = 16
The second atom neutral : atomic number = 8, mass number = 18
Both : isotopes
C. First atom = neutral, second atom anion (charge = -2)
D. Can exist in nature
The temperature of the system is highest when it is a
A. gas
B. liquid
C. plasma
D. solid
Answer:
gas
Explanation:
its either gas or plasma but gas should be it bc liquid and solid are cold
whats the unit for mass
Answer:
The unit for mass is the kilogram (Kg).
Explanation:
Hope this helped!! <3 good luckk!!
Metals bond with halogens to form colorless metal halides. During an experiment, chlorine water was added to a solution of potassium bromide. A record of the experiment is shown.
Experimental Record
Reactants Color of Reactants Color of Reactants after Mixing
cl,
Colorless solution
Deep yellow-orange colored solution is formed
KBT Colorless solution
Which of the following conclusions can be made about this chemical reaction based on the data? (1 point)
O Chlorine is more reactive than bromine.
Potassium bromide and chlorine do not react.
O Potassium metal is formed from a single replacement reaction.
O Bromine solution is colorless and is formed due to a single replacement reaction.
Answer:
O Chlorine is more reactive than bromine.
Explanation:
From this experiment we can conclude that chlorine is more reactive than bromine and it is the reason why the reaction is able to proceed.
The reaction is a single displacement reaction in which the position of an element in the activity series is very important. Since chlorine is more electronegative and highly reactive when compared to bromine, it will displace bromine from the solution of potassium bromide. So, we have product of potassium chloride and the bromide.number of atoms in 10090 g Ne (PLEASE HELP!!)
Answer:
3012.51×10²³ atoms of Ne
Explanation:
Given data:
Mass of Ne = 10090 g
Number of atoms = ?
Solution;
Formula:
Number of moles = mass/ molar mass
Molar mass of Ne = 20.17 g/mol
Number of moles = 10090 g/ 20.17 g/mol
Number of moles = 500.25 mol
Number of atoms:
1 mole contain 6.022×10²³ atoms
500.25 mol × 6.022×10²³ atoms / 1 mol
3012.51×10²³ atoms
what is the mass in grams of a sample of 7.3 x 10^23 molecules of (iodine heptafluoride) IF7
320 g IF₇
General Formulas and Concepts:Math
Pre-Algebra
Order of Operations: BPEMDAS
Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to RightChemistry
Atomic Structure
Reading a Periodic TableUsing Dimensional AnalysisAvogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.Explanation:Step 1: Define
7.3 × 10²³ molecules IF₇
Step 2: Identify Conversions
Avogadro's Number
Molar Mass of I - 126.90 g/mol
Molar Mass of F - 19.00 g/mol
Molar Mass of IF₇ - 126.90 + 7(19.00) = 259.9 g/mol
Step 3: Convert
Set up: [tex]\displaystyle 7.3 \cdot 10^{23} \ molecules \ IF_7(\frac{1 \ mol \ IF_7}{6.022 \cdot 10^{23} \ molecules \ IF_7})(\frac{259.9 \ g \ IF_7}{1 \ mol \ IF_7})[/tex]Multiply/Divide: [tex]\displaystyle 315.056 \ g \ IF_7[/tex]Step 4: Check
Follow sig fig rules and round. We are given 2 sig figs.
315.056 g IF₇ ≈ 320 g IF₇
If the object floats in water, is its density lower or higher?
Answer:
Its has a lower density. Think about it, a ship in the water is long because if it wasn't it would have a higher density and sink. The ship needs to diperse its weight across the water to make it less dense.
Explanation:
Your welcome! Have a great day!
Choose the statement below that correctly describes electrons.
a. Electrons have a positive charge and are lighter than protons
b. Electrons have a positive charge and are heavier than protons
c. Electrons have a negative charge and are heavier than protons
d. Electrons have a negative charge and are lighter than protons
Answer:
d. Electrons have a negative charge and are lighter than protons
Explanation:
The best statement that describes electrons is that electrons are negatively charged and are lighter than protons.
There are three known subatomic particles which are:
Protons which are the positively charged particles within an atom. Electrons are the negatively charged particles Neutrons do not carry any charges.The mass of the protons and neutrons are similar.
Electrons are lighter than both protons and neutrons.
What is in the solar system?
A. All the above
B. asteroids and comets
C. The sun and everything thing that orbits around it
D. planets and their moons
PLEASE HELP
Answer:
all of the above
Explanation:
all of this is in the solar system
Which statement accurately represents the properties of these moles.. help ASAP, teacher didn’t teach me this
Answer:
1 mole of O₂ has more mass compared to 1 mole of Na
Explanation:
1 mole oxygen atom and 1 mole of Na atom has the same number of particles.
A mole of any substance has the Avogadro number of particles which is
6.02 x 10²³
Mass of a substance = number of moles x molar mass
Molar mass of O₂ = 2(16) = 32g/mol
Molar mass of Na = 23g/mol
Mass of O₂ = 1 x 32 = 32g
Mass of Na = 1 x 23 = 23g
So, 1 mole of O₂ has more mass compared to 1 mole of Na
What does the GOES acronym stand for?
A. Geological Open Engineering System
B. Geostationary Opertational Environmental Satellite
C. Grandma Only Eats Spagetti
Answer:
B. Geostationary Operational Environmental Satellite
Explanation:
Hope this helps!
Answer:
B
Explanation:
I’m studying it for you!
3. If 12.5 grams of copper are reacted with excess chlorine gas, then 25.4 grams of
copper (II) chloride are produced. Calculate the theoretical yield and the percent
yield. Cu + Cl2 → CuCl2
Answer:
Percent yield = 99.6%
Theoretical yield = 25.5 g
Explanation:
Given data:
Mass of copper = 12.5 g
Mass of copper(II) chloride produced = 25.4 g
Theoretical yield = ?
Percent yield = ?
Solution:
Chemical equation:
Cu + Cl₂ → CuCl₂
Number of moles of copper:
Number of moles = mass/molar mass
Number of moles = 12.5 g / 63.5 g/mol
Number of moles = 0.19 mol
Now we will compare the moles of copper and copper chloride.
Cu : CuCl₂
1 : 1
0.19 : 0.19
Mass of CuCl₂: Theoretical yield
Mass = number of moles × molar mass
Mass = 0.19 mol × 134.45 g/mol
Mass = 25.5 g
Percent yield:
Percent yield = (actual yield / theoretical yield )×100
Percent yield = ( 25.4 g/ 25.5 g) ×100
Percent yield = 99.6%
Which of the following correctly shows the relationship, in terms of number of particles, of the three substances?
A. 1 mole of water < 1 mole of helium < 1 mole of aluminum
B. 1 mole of aluminum = 1 mole of helium = 1 mole of water
C. 1 mole of aluminum < 1 mole of helium < 1 mole of water
D. 1 mole of helium < 1 mole of aluminum < 1 mole of water
The correct option which shows the relation between particles of the three substances is 1 mole of aluminum = 1 mole of helium = 1 mole of water.
What is a particle?
A particle is a small part of matter.
The term refers to particles of all sizes, ranging from subatomic particles like electrons to visible particles like dust particles floating in sunlight.
The relationship of a number of particles of the substance can be calculated by Avogadro's law
Thus, the correct option is B. 1 mole of aluminum = 1 mole of helium = 1 mole of water
Learn more about particles
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7. A 10.0 cm3 sample of copper has a mass of 89.6 g. What is the density of copper?
Answer:
d = 8.96 g/cm³
Explanation:
Given data:
Volume of sample = 10.0 cm³
Mass of copper = 89.6 g
Density of copper = ?
Solution:
Formula:
d = m/v
d = density
m = mass
v = volume
by putting values,
d = 89.6 g/ 10.0 cm³
d = 8.96 g/cm³
Please help outttt:(
Explanation:
1)
2Fe+3Cl2 →2FeCl3
2)
CH4+2O2 → CO2 +2H2O
3)
SnO2+2H2 →2H2O +Sn
4)
2KOH + H2SO4 → K2SO4+2H2O
What is the percent composition of nitrogen in N 2 O
Answer:
28 %
Explanation:
Mass mass N2O = 28 + 16 = 44 mass nitrogen = 2 x 14 = 28 % nitrogen Chemistry.
Number 2 & 3 please !!<3
Answer:just for the ponits
Explanation:ima be a jenna
what is one example of a electromagnetic wave
Answer:
Examples of EM waves are radio waves, microwaves, infrared waves, X-rays, gamma rays, etc.
Answer:
Electromagnetic waves can be split into a range of frequencies. This is known as the electromagnetic spectrum. Examples of EM waves are radio waves, microwaves, infrared waves, X-rays, gamma rays, etc.
Explanation:
How many electrons does H have with a -1 charge
Answer:The electron has a negative charge and the proton has a positive charge, and these charges work against each other to make the electromagnetic force that holds the entire atom together.
Explanation:
This is the answer
A piece of mental with a mass of 106 g is placed in a 50 mL graduated cylinder.The volume rises from 20 mL to 31 mL. What is the destiny of the metal?
Answer:
9.64g/mL
Explanation:
Given parameters:
Mass of the metal = 106g
Volume of cylinder = 50mL
Volume difference = 31mL - 20mL = 11mL
Unknown:
Density of the metal = ?
Solution:
To find the density of the metal, we use;
Density = [tex]\frac{mass}{volume}[/tex]
Density = [tex]\frac{106}{11}[/tex] = 9.64g/mL
Which element below would most likely gain 3 electrons?
Answer:
Lithium
Explanation:
What compound do cells break down for energy in the process of cellular respiration?
O Oxygen
O Sunlight
Chloroplast
O Glucose
Answer:
Glucose
Explanation:
Glucose is broken down into water and carbon dioxide.
hope this helps! :)
The chemical equation below shows the photosynthesis reaction.
6CO2 + 6H2O → C6H12O6 + 6O2
A reaction uses 528 g of CO2. How many grams of water are used in this reaction?
Answer:
12
Explanation:
Which of the following statements is true about the relationship between atoms and molecules? A. Most atoms are bonded together to make a molecule. B. An atom can be seen by scientists, but a molecule cannot. C. Atoms and molecules are the same and have no differences.
Answer:
I believe the answer is A. molecules are larger than atoms so they should be visible and atoms and molecules are indeed different
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 correct option is option A.
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. Most atoms are bonded together to make a molecule. Molecules combine to form compounds.
Therefore, the correct option is option A.
To know more about atom, here:
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