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.
Learn more about chemical change,here:
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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.
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:
what were Lamarck's ideas about evolution and why were those ideas incorrect
What were Lamarck's ideas about evolution and Why were those ideas incorrect?
→ These and other examples show that Lamarck's theory does not explain how life formed and became the way it is. The other way that Lamarck's theory has been proven wrong is the study of genetics. Darwin knew that traits are passed on, but he never understood how they are passed on.
[tex]#CarryOnLearning[/tex]Glucose is a compound made from three elements: carbon, oxygen, and hydrogen. For glucose to be broken down into these elements, it must undergo _____.
A. filtration or distillation
B. an irreversible physical change, such as tearing or slicing
C. a reversible physical change, such as boiling or melting
D. a chemical change
Answer:
D ) Chemical Change
Explanation:
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
balance the following equations:
a. ____AgI + _____Na2S → _____Ag2S + _____NaI
b. ____Na3PO4 + ____HCl →_____NaCl + _____H3PO4
c. _____Ba3N2 + _____H2O →_____Ba(OH)2 + _____NH3
d. _____TiCl4 + _____H2O →_____TiO2 + _____HCl
e. _____CaCl2 + _____Na3PO4 →_____Ca3(PO4)2 + _____NaCl
Answer:
A. 2AgI + Na2S → Ag2S + 2NaI
B. Na3PO4 + 3HCl → 3NaCl + H3PO4
C. Ba3N2 + 6H2O → 3Ba(OH)2 + 2NH3
D. TiCl4 + 2H2O → TiO2 + 4HCl
E. 3CaCl2 + 2Na3PO4 → Ca3(PO4)2 + 6NaCl
Explanation:
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
in the structure of an atom why are protons present in the centre and are not pulled outside by the electrons as both are positively charged with some unit of charge?
Answer:
Electrons and protons are not positively charged
Explanation:
Neutrons are the only ones positively charged in the structure of an atom.... Also like charges repel which means a -ive and a - ive will repel when together
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!
Select the mixture which is capable of tolerating addition of a strong acid without altering the pH? a.) 1.0 M HCl, 1.0 M NaCl b.) 1.0 M NH3,1.0 M NaCl c.) 1.0 M HF, 1.0 M NaCl d.) 1.0 M HNO2, 1.0 M NaNO2 e.) none
Answer:
d.) 1.0 M HNO2, 1.0 M NaNO2
Explanation:
A buffer is a mixture that is capable of tolerating addition of a strong acid or base without altering the pH substantially.
A buffer is the mixture of a WEAK ACID AND ITS CONJUGATE BASE or a WEAK BASE AND ITS CONJUGATE ACID
In the problems:
a) HCl is a strong acid and NaCl a salt. NO buffer
b) NH3 is a weak base and NaCL a salt. NO buffer
c) HF is a weak acid and NaCl a salt. NO buffer.
d) HNO2 is a weak acid and NaNO2 its conjugate base. A BUFFER6. 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.
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☹
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!!!
A gas with a volume of 250 mL at a temperature of 293K is heated to 324K. What is the new volume of the gas?
V2 = 276 ml
Explanation:
Given:
V1 = 250 ml V2 = ?
T1 = 293K. T2 = 324K
Here, we use Charles's law:
V1/T1 = V2/T2
Solving for P2, we get
V2 = (T2/T1)V1
= (324K/293K)(250 ml)
= 276 ml
How many valence electrons does it have?
pls answer thank you
Answer:
One.
Explanation:
this is the structure of lithium which has valency 1 .Valency means no.electrons present in outermost shell or needed electrons to complete octet
50 POINTS PLEASE HELP!
A gas diffuses 1/7 times faster than hydrogen gas (H2).
What is the molar mass of the gas?
100.10 g/mol
98.78 g/mol
86.68 g/mol
79.98 g/mol
Answer: The molar mass of the gas is 9.878 g/mol.
Explanation:
According to Graham's law, the rate of diffusion is inversely proportional to square root of molar mass of gas.
[tex]Rate = \frac{1}{\sqrt{M}}[/tex]
where,
M = molar mass of gas
As given gas diffuses 1/7 times faster than hydrogen gas. So, its molar mass is calculated as follows.
[tex]\frac{R_{1}}{R_{2}} = \sqrt{\frac{M_{2}}{M_{1}}}\\[/tex]
where,
[tex]M_{1}[/tex] = molar mass of hydrogen gas
[tex]M_{2}[/tex] = molar mass of another given gas
[tex]R_{1}[/tex] = rate of diffusion of hydrogen
[tex]R_{2}[/tex] = rate of diffusion of another given gas = [tex]\frac{1}{7}R_{1}[/tex]
Substitute the values into above formula as follows.
[tex]\frac{R_{1}}{R_{2}} = \sqrt{\frac{M_{2}}{M_{1}}}\\\frac{R_{1}}{\frac{1}{7}R_{1}} = \sqrt{\frac{M_{2}}{2}}\\7 \times 1.414 = M_{2}\\M_{2} = 9.878 g/mol[/tex]
Thus, we can conclude that the molar mass of the gas is 9.878 g/mol.
Answer:
98.78 g/mol
Explanation:
Just took the test
What is the specific heat capacity of silver metal if 110.00 g of the metal
absorbs 396 J of heat and the temperature rises 15.0°C ?
Answer:
"0.24 J/g.k" is the appropriate solution.
Explanation:
Mass of substance,
m = 110.00 g
Heat,
q = 396 J
Change in temperature,
ΔT = 15.0°C
Now,
The specific heat will be:
⇒ [tex]q=ms \Delta T[/tex]
On putting the given values, we get
⇒ [tex]396=110.00\times s\times 15.0[/tex]
⇒ [tex]396=s\times 1650[/tex]
⇒ [tex]s=\frac{396}{1650}[/tex]
⇒ [tex]=0.24 \ J/g.k[/tex]
22.4 liters of CO2 at STP, 0◦C and 1 atm,
contains how many molecules? (Assume CO2
is an ideal gas.)
Answer:
There are [tex]6.01\times 10^{23}[/tex] number of molecules.
Explanation:
Given that,
Volume, V = 22.4 L
Temperature, T = 0°C = 273.15 K
Pressure, P = 1 atm = 1.013 bar
We need to find the number of molecules. Let there are n number of molecules. We know that, ideal gas law is as follows :
[tex]PV=nRT\\\\n=\dfrac{PV}{RT}\\\\n=\dfrac{1.013\times 22.4}{0.08 314\times 273.15}[/tex]
n = 0.999 moles
No. of molecules,
[tex]N=n\times N_A\\\\=0.999\times 6.023\times 10^{23}\\\\N=6.01\times 10^{23}[/tex]
So, there are [tex]6.01\times 10^{23}[/tex] number of molecules.
Science
How is the total magnification of a
cell calculated?
Help me plz plz bbbbb
Answer:
The respiratory system is the network of organs and tissues that help you breathe. basically your airways, lungs, and blood vessels so you quite literally need these to survive I mean your muscles need oxygen to function and your brain needs oxygen to function so without your respiratory system you wouldn't be able to move much and you would quickly pass out and die from the lack of oxygen to your brain there are other body processes that need oxygen as well but these are just two examples.
Explanation:
Answer:
Maybe it’s dark ??????????????
Explanation:
Hm
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!
How many joules of heat is needed when 5 g of water is heated from 25°C to 75°C?
Answer:
1045 J
Explanation:
By using the formula Eh= mass×specific heat capacity × change in tempreture
With it being a known fact that the specific heat capacity of water is 4.16g/j/°c
Gather data: experiment with a variety of initial concentrations of no2 and n2o4. for each set of initial concentrations, use the gizmo to determine the equilibrium concentrations of each substance. in the last column, find kc for that trial. run three trials for each set of initial conditions.
Solution :
[tex]$H_2 +I_2\rightleftharpoons 2HI$[/tex]
Initial concentration Equilibrium concentration [tex]$K_c=\frac{[HI]^2}{[H_2][I_2]}$[/tex]
(mol/L) (mol/L)
[tex]$[H_2]$[/tex] [tex]$[I_2]$[/tex] [tex]$[HI]$[/tex] [tex]$[H_2]$[/tex] [tex]$[I_2]$[/tex] [tex]$[HI]$[/tex]
[tex]$2.4 \times 10^{-2}$[/tex] [tex]$1.38 \times 10^{-2}$[/tex] 0 [tex]$1.14 \times10^{-2}$[/tex] [tex]$0.12 \times 10^{-2}$[/tex] [tex]$2.52 \times 10^{-2}$[/tex] 46.42
[tex]$2.4 \times 10^{-2}$[/tex] [tex]$1.68 \times 10^{-2}$[/tex] 0 [tex]$0.92 \times10^{-2}$[/tex] [tex]$0.20 \times 10^{-2}$[/tex] [tex]$2.96 \times 10^{-2}$[/tex] 47.61
[tex]$2.4 \times 10^{-2}$[/tex] [tex]$1.98 \times 10^{-2}$[/tex] 0 [tex]$0.77 \times10^{-2}$[/tex] [tex]$0.31 \times 10^{-2}$[/tex] [tex]$3.34 \times 10^{-2}$[/tex] 46.73
[tex]$2.4 \times 10^{-2}$[/tex] [tex]$1.76 \times 10^{-2}$[/tex] 0 [tex]$0.92 \times10^{-2}$[/tex] [tex]$0.22 \times 10^{-2}$[/tex] [tex]$3.08 \times 10^{-2}$[/tex] 46.86
[tex]$0$[/tex] [tex]$0$[/tex] [tex]$3.04 \times 10^{-2}$[/tex] [tex]$0.345 \times10^{-2}$[/tex] [tex]$0.345 \times 10^{-2}$[/tex] [tex]$2.35 \times 10^{-2}$[/tex] 46.39
[tex]$0$[/tex] [tex]$0$[/tex] [tex]$7.58 \times 10^{-2}$[/tex] [tex]$0.86 \times10^{-2}$[/tex] [tex]$0.86 \times 10^{-2}$[/tex] [tex]$5.86 \times 10^{-2}$[/tex] 46.42
Average [tex]$K_c=46.738$[/tex]
Oxygen by itself is not harmful; _______, it can become harmful when combined with carbon. *
1 point
however
for instance
in summary
namely
Answer:
what's the question?? I see nothing
Answer:
However
Explanation:
sounds the best and makes since
Los ácidos y el pH son muy importantes en la digestión de los alimentos. Pero ¿por qué se pone en riesgo la salud con lo que comes?
Answer:
Plssssssssd can you translate to English???
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 :)
Explain how failing to conserve water can lead to an increase in water contamination.
Answer:
Failure to conserve water during irrigation can lead to an increase in pollution that results from runoff. Natural filters are diminished by the overuse of water resources, which leads to an increase in water contamination that would have been filtered by these natural sources.
Explanation:
Answer:
a. Overirrigating fields causes an increase in pollution that results from runoff.
b. Natural water filters are depleted by the overuse of water.
c. Sewage systems are more likely to fail due to greater demand, causing higher chances of water contamination.
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.
Select the correct choices to complete the sentence.
In the ionic solid sodium chloride (NaCl), there is a________
ratio of sodium ions to chlorine ions.
one and half to one
tow to one
one to two
one to one
Answer:
one to one
Explanation:
Answer:
In the ionic solid sodium chloride, there is one to one ratio of sodium ions to chloride ions