Answer:
The correct answer is "85.71 mg".
Explanation:
The given values are:
Mass of drug,
= 3.0 mg
Mass percentage,
= 3.5%
As we know,
⇒ [tex]Mass \ percent = \frac{Mass \ of \ drug}{Mass \ of \ solution}\times 100[/tex]
Or,
⇒ [tex]Mass \ of \ solution = \frac{Mass \ of \ drug}{Mass \ percent}\times 100[/tex]
On substituting the values, we get
⇒ [tex]=\frac{3.0}{3.5}\times 100[/tex]
⇒ [tex]=0.8571\times 100[/tex]
⇒ [tex]=85.71 \ mg[/tex]
what are the best topics to write a project work on EVS and Chemistry
Answer:
It is better to do chemistry
Explanation:
So that you will learn more of chemicals
Please hurry Which of the following statements is true?
• A positively charged atom has more electrons than protons.
• A positively charged atom has more protons than neutrons.
• A positively charged atom has more neutrons than protons.
• A positively charged atom has no electrons.
• A positively charged atom has more protons than electrons.
Answer:
E, answer 5, A positively charged atom has more protons than electrons.
Explanation:
The ionization energies required to remove successive electrons from one mole of calcium atoms are 590 kJ/mol, 1145 kJ/mol, 4912 kJ/mol, and 6474 kJ/mol. The most common ion of calcium is probably
Answer:
Ca^2+
Explanation:
As we know, more energy is required to remove an electron from a positively charged ion than is required to remove an electron from a neutral atom. Hence, the second ionization energy of calcium is greater than its first ionization energy.
However, the third and fourth ionization energies of calcium are much higher than the second ionization energy because they involve removal of electrons from an inner filed shell. This process requires a lot of energy and is often not feasible.
Hence, the most common ion of calcium must be Ca^2+ where only two electrons are removed from calcium.
Calculate the mass of an object that has a density of 3.52g/cm^3 and
a volume of 5000 cm^3. Note that Mass = Volume X Density
Answer:
17.6kg
Explanation:
mass = Volume × Density
mass = 5000cm^3 × 3.52g/cm^3
mass = 17600g = 17.6kg
A student was asked to determine the activity of four unknown metals W,X,Y and, Z.
Answer:
BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB
The activity of four unknown metals based on their chemical changes is option B.
What is a chemical change?Chemical changes are defined as changes which occur when a substance combines with another substance to form a new substance.Alternatively, when a substance breaks down or decomposes to give new substances it is also considered to be a chemical change.
There are several characteristics of chemical changes like change in color, change in state , change in odor and change in composition . During chemical change there is also formation of precipitate an insoluble mass of substance or even evolution of gases.
There are three types of chemical changes:
1) inorganic changes
2)organic changes
3) biochemical changes
During chemical changes atoms are rearranged and changes are accompanied by an energy change as new substances are formed.
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1.How many moles of each element are in 0.0250 mol of K 2 Cr O 4? 2. How many moles of ammonium ions are in 4.50 mol of (N H 4 ) 2 CO 3 ? With all the process to see where you get the answers please
Answer:
1. 0.0500 moles K, 0.0250 moles Cr and 0.1000 moles O.
2. 9.00 moles ammonium ions are present.
Explanation:
1. In 1mol of K2CrO4 there are 2 moles of K, 1 mole of Cr and 4 moles of O.
The moles in 0.0250 moles K2CrO4 are:
0.0250mol * 2 = 0.0500 moles K
0.0250mol * 1 = 0.0250 moles Cr
0.0250mol * 4 = 0.1000 moles O
2. In 1 mole of (NH4)2CO3 there are 2 moles of ammonium ions, NH₄⁺.
In 4,50 moles are:
4.50 moles * 2 = 9.00 moles ammonium ions are present
True or False all non - metal elements are gassed at room temperature.
Answer:
false
Explanation:
you have bromine , its a non metal and liquid in room temperature
3. A PS6 plugged into a 120 V outlet uses 3 Amps. What is the Resistance rating of
the power cord?
voltage: V=
current: 1 =
resistance: R=
V=IxR
1=VR R
Underline/Bold Which Equation we are going to use:
= V
Plug in the numbers from above and solve for our answer:
Answer:
R = 40 ohms
Explanation:
Given that,
The voltage of outlet, V = 120 V
Current flowing through the device, I = 3 A
We need to find the Resistance rating of the power cord. Let the resistance is R. We know that,
Ohm's law, V = IR
Put all the values,
[tex]R=\dfrac{V}{I}\\\\R=\dfrac{120}{3}\\\\R=40\ \Omega[/tex]
So, the resistance rating of the power cord is equal to 40 ohms.
2CO +0, 200, what is the mole ratio of carbon monoxide to carbon
dioxide
A 1.2
B 2.2
C 2:1
D 3:1
Answer:
B. 2.2
Explanation:
When H forms a bond with H2O to form the hydronium ion H3O , this bond is called a coordinate covalent bond because
Answer:
both bonding electrons come from the oxygen atom
Explanation:
A coordinate covalent bond is said to be formed when an electron pair is donated into a empty orbital of an atom from a filled orbital of another atom.
In this type of covalent bond, the shared electron pair is furnished by only one of the bonding species.
The bonding between H^+ and H2O to form H3O^+ involves donation of a lone pair of electrons on oxygen into the empty 1s orbital of H^+ hence the two bonding electrons come from oxygen. This is why the bond is called a coordinate covalent bond.
Which statement best describes what makes a base weak? A base is weak when it forms few ions in water. A base is weak when only a little of it is dissolved in water. A base is weak when its concentration is high. A base is weak when it totally forms ions in water.
Answer:
A base is weak when only a little of it is dissolved in water
Explanation:
Answer: B.) A base is weak when only a little of it is dissolved in water
Hope this helps :)
6. The fusion of 4 H-1 nuclei to produce two positrons and one other nuclei.
Explanation:
Normally, fusion involves two heavy hydrogen nuclides but since we have 4 light hydrogen nuclides, two of which underwent positron emission, thus changing two protons into neutrons plus 2 positrons and 2 neutrinos. The resulting nucleus from this fusion reaction is an He-4 nucleus.
45.6 grams of CH4 is placed into a 275 mL container at 55.00C. What is the pressure inside the container in atm?
Given-
Mass of CH4 - 45.6 grams
Molar mass of CH4 - 16.04 g/mol
volume - 275mL
Temperature- 55°C
Solution,
moles of methane (CH4) n = 45.6/16.04
= 2.84 moles
Using Formula,
Pv = nRT
P*275 = 2.84*8.314*55
P = 1298.64/275
P = 4.72 Atm.
Answer - The pressure inside the container in atm is 4.72.
45.6 grams of CH4 is placed into a 275 mL container at 55.00 C. The pressure is 4.72 atm.
What is partial pressure?The pressure that one of the gases in a mixture would exert if it were in the same volume on its own.
Given the mass is 45.6 grams
The volume is 275 L
Temperature is 55.00 C.
Calculate the moles
[tex]\rm Number\;of \;moles= \dfrac{mass}{molar\;mass}\\\\\rm Number\;of \;moles= \dfrac{45.6}{16.04} = 2.84 moles[/tex]
Now, calculating the pressure
PV = nRT
[tex]P\times 275 = 2.84\times 8.314\times 55 = 4.72 atm.[/tex]
Thus, the pressure inside the container in is 4.72 atm.
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The boat shown in the photo below is moving along at a constant 20 miles per hour. Is the boat accelerating? Question 3 options: A. No because it is not speeding up B. Yes because it is changing direction C. No because it is not slowing down D. Yes because the velocity is staying constant
Answer:
A
Explanation:
If its going at a constant speed it will not accelarate wich means to speed up.
Suggest whether potassium metal can be used to react with an acid to prepare a soluble salt. Explain your answer.
Yes, potassium metal can be used to react with an acid to prepare a soluble salt.
Acids react with metals to yield the corresponding metal salt and hydrogen gas.
One of the properties of metals is their ability to react with dilute acids to yield a soluble salt and hydrogen gas. This is a common reaction for all metals that are above hydrogen in the activity series.
Potassium can react with a hypothetical acid HB as follows;
2K(s) + 2HB(aq) ------> 2KB(aq) + H2(g)
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A 2.0 L flask contains nitrogen and oxygen gases at 25°C. The total pressure is 0.91 atm and contains 0.050 mol of nitrogen. Calculate the partial pressure of oxygen and moles of oxygen present
Answer:
.025 ml 02
Explanation:
I made a pdf and pasted it in and etc
The carbon dioxide is released when limestone is heated during the
production of _____?
Carbon dioxide is released when limestone is heated during the production of [tex]\sf\purple{cement}[/tex]. ✔
[tex]\circ \: \: { \underline{ \boxed{ \sf{ \color{green}{Happy\:learning.}}}}}∘[/tex]
A chemist mixes 50.0mL of a 1.0M NaOH solution with 50.0mL of a 1.0M Ba(OH)2 solution. Assuming the two solutions are additive, what is the pH of the resulting solution
Answer:
[tex]pH=14.2[/tex]
Explanation:
Hello there!
In this case, according to the information in this problem, and considering these two bases are strong, it is necessary for us to calculate the total moles of OH ions as shown below:
[tex]n_{OH^-}^{from\ NaOH}=0.050L*1.0mol/L=0.050mol\\\\n_{OH^-}^{from\ Ba(OH)_2}=0.050L*1.0mol/L*2=0.10mol\\\\n_{OH^-}^{tot}=0.15mol[/tex]
Now, the as the solutions are additive, the total volume is then 0.100 L and the concentration:
[tex][OH^-]=\frac{0.15mol}{0.100L}=1.5[/tex]
And therefore, the pH is:
[tex]pH=14+log(1.5)\\\\pH=14.2[/tex]
Regards!
Science
How is the total magnification of a
cell calculated?
Can someone please help with these questions!! I would really appreciate it
Answer: water
Explanation: those elements all react to water , so the answer would be water . :)
5.) If 6 moles of Oxygen Gas (O2) are produced in the reaction below, how
many grams of Potassium Chloride (KCI) are also produced? *
2 KCIO3 → 2 KCI + 3 O2
Answer:
im really sorry but i dont no☹
Can someone help me pleaseee
Answer:
D.
Explanation:
Answer
0°C
Explanation:
substance be formed in it's solid state
When we send electricity to pass through electrolysis jar we see gas bubble around both electrodes. Water electrolysis produces 30cm3 at cathode. a. What gas does it appear at each electrode? b. What would you do to identify the gas in the test tubes at each electrode? c. Calculate the volume of gas which appears at anode.
Answer:
a) anode - hydrogen gas
cathode - oxygen gas
b) hydrogen gas - The gas burns with a pop sound
Oxygen gas - The gas rekindles a glowing splint
c) The volume of gas produced at the anode is 60cm3
Explanation:
The electrolysis of water produces two volumes of hydrogen at the anode and one volume of oxygen at the cathode.
The hydrogen gas burns with a pop sound. It is easily identified by this test. Also, oxygen is known to rekindle a glowing splint and this is a commonly used test for oxygen gas.
Since the ratio of hydrogen produced at the anode to oxygen produced at the cathode is 2:1 by volume; then when 30cm3 of oxygen is produced at the cathode, 60cm3 of hydrogen is produced at the anode.
which of the follwing is false ? A . the mass of proton is heavier than electron . B . protons and electron are found in nucleus C . Nucleus is very small but massive D . Neutrons are neutral particles
Answer:
C
Explanation:
The nucleus is very dense
A student performed the following reaction in his Chemistry class: Zn + 2HCl ---> ZnCl2+H2. He started with 32.70 g of Zn metal and 18.23 g HCl and got 60.1 g of of ZnCl2.
(I) How much ZnC12 should he have produced?
(II) What was his percentage yield?
(III) If the 32.70 g of Zinc that he started with contained impurities (materials other than Zinc), will this support the student's percentage yield?
Explain briefly.
Answer:
(I) [tex] m_{ZnCl_{2}} = 34.07 g [/tex]
(II) [tex] \% y = 176.4 \% [/tex]
(III) The presence of impurities in the 32.70 g of zinc will support the student's percentage yield.
Explanation:
The reaction is:
Zn + 2HCl → ZnCl₂ + H₂
(I) To find the number of moles of ZnCl₂ we need to calculate the number of moles of the reactants.
[tex] n_{Zn} = \frac{m}{A} [/tex]
Where:
m: is the mass
A: is the standard atomic weight
[tex] n_{Zn} = \frac{32.70 g}{65.38 g/mol} = 0.50 moles [/tex]
[tex] n_{HCl} = \frac{18.23 g}{36.458 g/mol} = 0.50 moles [/tex]
If 1 mol of Zn reacts with 2 moles of HCl, the number of moles of Zn needed to react with 0.50 moles of HCl is:
[tex] n_{Zn} = \frac{1 mol Zn}{2 moles HCl}*0.50 moles HCl = 0.25 moles [/tex]
Then, the limiting reactant is HCl. Now, we can find the number of moles of ZnCl₂ by knowing that 2 moles of HCl produce 1 mol of ZnCl₂.
[tex] n_{ZnCl_{2}} = \frac{1 mol ZnCl_{2}}{2 moles HCl}*0.50 moles = 0.25 moles [/tex]
Finally, the mass of ZnCl₂ that he has produced is:
[tex] m_{ZnCl_{2}} = n_{ZnCl_{2}}*M = 0.25 moles*136.286 g/mol = 34.07 g [/tex]
(II) The percentage yield can be found with the following equation:
[tex] \% y = \frac{m_{e}}{m_{t}} \times 100 [/tex]
Where:
[tex] m_{e}[/tex]: is the experimental mass = 60.1 g
[tex] m_{t}[/tex]: is the theoretical mass = 34.07 g
Hence, the percentage yield is:
[tex] \% y = \frac{60.1 g}{34.07 g} \times 100 = 176.4 \% [/tex]
(III) The presence of impurities in zinc will explain why the percentage yield is greater than 100% because the mass of the impurities will make the mass of zinc bigger than its mass without impurities. If there were no impurities in the zinc, its mass would be smaller and thus the percent yield.
I hope it helps you!
The primary function of a chloroplast is to -
F . Convert food into energy a cell can use
G . Control the function of a cell and control genetic traits
H . Convert radiant energy into chemical energy through photosynthesis
J . Store water and nutrients
Please help!!!
define restivity and conductivity?
Answer:
Electrical resistivity is a property of a material that tells you how much it resists the flow of electric current, while conductivity quantifies how easily current flows.
The volume of a gas decreases to half of its original volume, but the gas maintains the same number of moles and temperature. According to the ideal gas law, what will most likely happen to the pressure
Imagine you had HCl with a concentration of exactly 0.10 mol/dm3. If 0.023 dm3 of a sodium hydroxide solution, NaOH (aq), could exactly neutralize 0.040 dm3 of the HCl solution, what is the concentration of the NaOH (aq)
Answer:
Explanation:
Step 1: Calculate the amount of sodium hydroxide in moles
Volume of sodium hydroxide solution = 25.0 ÷ 1,000 = 0.0250 dm3
Rearrange:
Concentration in mol/dm3 =
Amount of solutein mol = concentration in mol/dm3 × volume in dm3
Amount of sodium hydroxide = 0.100 × 0.0250
= 0.00250 mol
Step 2: Find the amount of hydrochloric acid in moles
The balanced equation is: NaOH(aq) + HCl(aq) → NaCl(aq) + H2O(l)
So the mole ratio NaOH:HCl is 1:1
Therefore 0.00250 mol of NaOH reacts with 0.00250 mol of HCl
Step 3: Calculate the concentration of hydrochloric acid in mol/dm3
Volume of hydrochloric acid = 20.00 ÷ 1000 = 0.0200 dm3
Concentration in mol/dm3 =
Concentration in mol/dm3 =
= 0.125 mol/dm3
Step 4: Calculate the concentration of hydrochloric acid in g/dm3
Relative formula mass of HCl = 1 + 35.5 = 36.5
Mass = relative formula mass × amount
Mass of HCl = 36.5 × 0.125
= 4.56 g
So concentration = 4.56 g/dm3
5F248+ 2NH3(8) ► NF418 + 6HF
a) If you start with 3.6 g of NH, and excess F2, how many liters of HF at STP can you make?
Answer:
14.2L at STP
Explanation:
Based on the problem, 2 moles of NH3 produce 6 moles of HF. To solve this question we have to convert the mass of NH3 to moles. With the chemical equation find the moles of HF and using PV = nRT find the liters of HF:
Moles NH3 -Molar mass: 17.031g/mol-
3.6g NH3 * (1mol / 17.031g) = 0.211 moles NH3
Moles HF:
0.211 moles NH3 * (6mol HF / 2mol NH3) = 0.634 moles HF
Volume HF
PV = nRT; V = nRT/P
Where V is volume in liters, n are moles of the gas = 0.634 moles, R is gas constant = 0.082atmL/molK, T is absolute temperature = 273.15K at STP and P is pressure = 1atm at STP.
Replacing:
V = 0.634moles*0.082atmL/molK*273.15K / 1atm
V = 14.2L at STP