Answers
Answer:
a. HF
Explanation:
Related Questions
To be effective, a certain drug must not drop below 15 mg in the body. A 120
mgs of that drug was administered to a patient. How much time will it take for that drug to reach the 15 mg minimum level. The drug's half-life is 30 minutes.(show how you arrived at your response)
Answers
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.
Answers
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.
why do stars appear to be bigger in the night?
Answers
Answer: in the daytime the sun is out so the stars are not visible becuase the suns reflection! At night When you gaze at the constellations, every star produces an image that's the same size, but your retina isn't sensitive enough to respond to the outer parts of those images except for the brighter stars — which therefore look bigger than the fainter ones.
Explanation:
This is what I found on goog.le a while ago now it might actually help if I’m wrong I apologiz, I hope this was your quistion!
Which element below would most likely gain 3 electrons?
Answers
Answer:
Lithium
Explanation:
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
Answers
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%
How many grams of K2Cr2O7, are soluble in 100 g of
water at 95 °C?
Answers
Answer:
75 grams
Explanation:
At 95 °C, you can dissolve up to 75 grams of K2Cr2O7 in 100 mL of water.
What is solubility?The solubility of a substance in a particular solvent is the maximum amount of that substance that can dissolve in the solvent at a given temperature. The solubility of a substance can be affected by factors such as temperature, pressure, and the presence of other substances.
For K2Cr2O7, the solubility in water is highly dependent on temperature. At 95 °C, the solubility of K2Cr2O7 in water is approximately 75 g/100 mL. This means that at 95 °C, you can dissolve up to 75 grams of K2Cr2O7 in 100 mL of water. Since 100 g of water is equivalent to 100 mL, you can dissolve up to 75 grams of K2Cr2O7 in 100 g of water at 95 °C.
Learn more about solubility, here:
https://brainly.com/question/28170449
#SPJ2
Which element has the following complete electron configuration : 1s22s22p63s23p64s23d5?
Answers
Answer:
Manganese
Explanation:
The electronic configuration of the atom is:
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁵
The powers in this configuration is the number of electrons in each orbital:
2 + 2 + 6 + 2 + 6 + 2 + 5 = 25
The compound has 25 electrons and it is Manganese
The electron configuration 1s22s22p63s23p64s23d5 corresponds to the element manganese (Mn).
In the electron configuration provided:
1s2 represents the filling of the 1s subshell with two electrons.
2s2 represents the filling of the 2s subshell with two electrons.
2p6 represents the filling of the 2p subshell with six electrons.
3s2 represents the filling of the 3s subshell with two electrons.
3p6 represents the filling of the 3p subshell with six electrons.
4s2 represents the filling of the 4s subshell with two electrons.
3d5 represents the filling of the 3d subshell with five electrons.
Based on this electron configuration, we can correctly identify the element as manganese (Mn), which has an atomic number of 25.
Know more about electron configuration:
https://brainly.com/question/29157546
#SPJ6
a compound has hydrogen ion and nitrate ion in solutionstate what is the name of that compound
Answers
Answer:
This compound is HNO2
Explanation:
HNO2 ----> H+ + NO2
When metals and non metals combine in fixed proportion then a chemical compound is formed So, the compound that will be formed from hydrogen ion and nitrate ion is Hydrogen nitrate.
What is chemical formula?
Chemical formula is a formula where cation and anion combine to form a molecule in fixed proportion. Metals combine in form of cation and non metals combine in form of anion.
Cation is the species that give electron and attain positive charge while anion is a species which gain electron and attains negative charge so when anion and cation combine in fixed ration the the overall charge of the molecule is zero that is molecule is neutral, the charge over cation and anion is also called oxidation state.
Therefore, the compound that will be formed from hydrogen ion and nitrate ion is Hydrogen nitrate.
To learn more about Chemical formula, here:
https://brainly.com/question/28522480
#SPJ2
And this one please thank you.
Answers
Answer:
E
Explanation:
Look at bottom numbers.
90 → 88 + x
it means,
90=88+x
hence x = 2
it is also valid for top numbers.
230=226+y
y = 4
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?
Answers
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
If different atoms can come together to form living and nonliving things, why is there a limit to different combinations we encounter around the universe?
Answers
Explanation:
There is a limit to different things we encounter around the universe due to a lot of reasons.
Some combinations takes place under special conditions due to the activation energy barrier present.To overcome these barriers, some catalysts that are not readily available are needed. This reduces the combination of some atoms in nature.
Also, the right temperature and pressure conditions might not be present. For most reactions to occur, the right conditions must be made available by nature.This and many more reasons limits the combination of chemical substances.
There is a limit to different things we encounter around the universe due to a lot of reasons:
Some combinations takes place under special conditions due to the activation energy barrier present. To overcome these barriers, some catalysts that are not readily available are needed. This reduces the combination of some atoms in nature. Also, the right temperature and pressure conditions might not be present. For most reactions to occur, the right conditions must be made available by nature.So, for a chemical reaction to occur there are certain parameters that need to taken into consideration for a chemical reaction to actually takes place.
Learn more:
brainly.com/question/21568405
whats the unit for mass
Answers
Answer:
The unit for mass is the kilogram (Kg).
Explanation:
Hope this helped!! <3 good luckk!!
The Faruq family uses 548 liters of water per day.
The Chammas family uses 3 times as much water
per day.
Answers
Answer:
11508 liters
Explanation:
The Faruq family uses 548 liters of water per day. The Chammas family uses 3 times as much water per day. How much water does the Chammas family use per week?
Solution:
The amount of water used by the Chammas family is three times that of the Faruq family per day, hence:
Amount of water used by Chammas family in a day = 3 * water used by Faruq family in a day
Amount of water used by Chammas family in a day = 3 * 548 = 1644 liters
The amount of water used by the Chammas family in a week = 1644 liters per day * 7 days in a week = 11508 liters
Therefore 11508 liters of water was used by the Chammas family in a week
The way Earth's rotation makes winds curve.
Answers
Answer:
it is called the prevailing westerlies
Explanation:
What is the mass in grams of 0.40 moles of sodium borohydrate NaBH4
Answers
Answer:
Mass = 15.12 g
Explanation:
Given data:
Mass of sodium borohydride = ?
Number of moles of sodium borohydride =0.40 mol
Solution:
Formula:
Mass = number of moles / molar mass
Molar mass of sodium borohydride = 37.8 g/mol
By putting values,
Mass = 0.40 mol × 37.8 g/mol
Mass = 15.12 g
When a substance has large or strongly-attracted particles, they do not flow freely. For example, water flows very quickly compared to honey. Which property of liquids does this example illustrate?
Answers
Answer:
Viscosity
Explanation:
Viscosity is how thick a liquid is due to internal friction.
Which of the following reactions would have a decrease in entropy?
A. 2H20(g) → 2H2(g) + O2(9)
B. 2503(9) ► 2502(g) + O2(g)
C. 2NH3(9) ► N2(g) + 3H2(9)
D. 2NO2(g) → N204(9)
Answers
Answer:
D. 2NO2(g) → N204(9)
Explanation:
A p e x
2NO[tex]_2[/tex](g) → N[tex]_2[/tex]O[tex]_4[/tex](g) reactions would have a decrease in entropy. Therefore, the correct option is option D.
What is entropy?Entropy is a measureable physical characteristic and a scientific notion that is frequently connected to a condition of disorder, unpredictability, or uncertainty. From classical thermodynamic, where it was originally recognized, towards the microscopic explanation of nature within statistical physics, the name and concept are employed in a variety of disciplines.
It has numerous applications in physics and chemistry, biological systems and how they relate to life, cosmology, economics, society, weather science, and information systems, especially the exchange of information. 2NO[tex]_2[/tex](g) → N[tex]_2[/tex]O[tex]_4[/tex](g) reactions would have a decrease in entropy.
Therefore, the correct option is option D.
To know more about entropy, here:
https://brainly.com/question/14131507
#SPJ7
How does the number of molecules in 1 mol of oxygen compare with the number of molecules in 1 mol of nitrogen?
1 mol of oxygen has fewer molecules.
1 mol of oxygen has more molecules.
Each sample has the same number of molecules.
The molecules cannot be compared without knowing the mass.
Answers
Answer:
Each sample has the same number of molecules.
Explanation:
Just took the quiz on edge 2021
Taking into account the definition of Avogadro's number, each sample has the same number of molecules.
Avogadro's NumberAvogadro's Number or Avogadro's Constant is called the number of particles that make up a substance (usually atoms or molecules) and that can be found in the amount of one mole of said substance. Its value is 6.023×10²³ particles per mole.
Avogadro's number applies to any substance.
This caseAvogadro's number applies to any substance. This means that the number of molecules in 1 mol of oxygen is equal to the number of molecules in 1 mol of nitrogen.
Finally, the correct answer is the third option: each sample has the same number of molecules.
Learn more about Avogadro's Number:
brainly.com/question/1445383
brainly.com/question/1528951
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
Answers
Answer:
all of the above
Explanation:
all of this is in the solar system
How many moles and atoms are there in 60 grams of Calcium?
Answers
Answer:
The moles present in 60 g of calcium are 1.5 moles.
Answer:
In 60 grams there are 1,5 mols
Explanation:
Please help outttt:(
Answers
Explanation:
1)
2Fe+3Cl2 →2FeCl3
2)
CH4+2O2 → CO2 +2H2O
3)
SnO2+2H2 →2H2O +Sn
4)
2KOH + H2SO4 → K2SO4+2H2O
what is the mass in grams of a sample of 7.3 x 10^23 molecules of (iodine heptafluoride) IF7
Answers
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
How many electrons does H have with a -1 charge
Answers
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
Enter a complete ionic equation to show the reaction of aqueous Hg2(NO3)2 with aqueous sodium chloride to form solid Hg2Cl2 and aqueous sodium nitrate. Express your answer as a complete ionic equation. Identify all of the phases in your answer.
Answers
Answer: [tex]Hg_2^{2+}(aq)+2NO_3^-(aq)+2Na^+(aq)+2Cl^-(aq)\rightarrow Hg_2Cl_2(s)+2Na^+(aq)+2NO_3^-(aq)[/tex]
Explanation:
A double displacement reaction is one in which exchange of ions take place. The salts which are soluble in water are designated by symbol (aq) and those which are insoluble in water and remain in solid form are represented by (s) after their chemical formulas.
A double displacement reaction in which one of the product is formed as a solid is called as precipitation reaction.
The balanced chemical equation is:
[tex]Hg_2(NO_3)_2(aq)+2NaCl(aq)\rightarrow Hg_2Cl_2(s)+2NaNO_3(aq)[/tex]
The complete ionic equation will be :
[tex]Hg_2^{2+}(aq)+2NO_3^-(aq)+2Na^+(aq)+2Cl^-(aq)\rightarrow Hg_2Cl_2(s)+2Na^+(aq)+2NO_3^-(aq)[/tex]
If the object floats in water, is its density lower or higher?
Answers
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!
What is the product(s) of the reaction below?
2Al(s) + Fe2O3(s) ---> Al2O3(s) + 2Fe(s)
A. Solid aluminum oxide and solid iron
B. Solid aluminum
C. Saturated aluminum oxide and saturated iron
D. Iron(III) oxide and aluminum oxide
Answers
Answer:
A. Solid aluminum oxide and solid iron
Explanation:
The reaction equation is given as:
2Al + Fe₂O₃ → Al₂O₃ + 2Fe
The species on the left hand side are the reactants
Those on the right hand side of the expression are the products.
The products are:
Al₂O₃ and Fe
These are solid aluminum oxide and solid iron
Are the activities exothermic or endothermic?
Answers
Answer:
The first 5 are exothermic reaction because heat is in product means heat is evolved or given out.
And last no reaction shows that heat is required so last reaction is endothermic reaction.
Explanation:
And heat is evolved in exothermic reaction and heat is absorbed in endo thermic reaction
An element is a specific type of atom (true or false)
Answers
Answer:
True
Explanation:
An element is pure substance that conatin only one type of atom
Answer:
true
Explanation:
the element hydrogen is made from atom
A hydrogen atom absorbs a photon radiation causing an electron to jump from level one to level two. If the photon/radiation has a wavelength of 5.62 x 10^-3 m to calculate the frequency of the radiation absorbed and the energy change of the electron
Answers
Answer:
1.
First of all, let's convert the energy of the absorbed photon into Joules:
The energy of the photon can be rewritten as:
where
h is the Planck constant
c is the speed of light
is the wavelength of the photon
Re-arranging the formula, we can solve to find the wavelength of the absorbed photon:
2. 1.24 eV
In this case, when the electron jumps from the n=4 level to the n=3 level, emits a photon with wavelength
So the energy of the emitted photon is given by the formula used previously:
and using
we find
converting into electronvolts,
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.
Answers
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:
https://brainly.com/question/13518322
#SPJ2