Answer:
1. A
2. B
3. B
4. A
5. B
Explanation:
1. Recommended. That way cross-contamination is prevented.
2. Not recommended. The inner mechanism of the micropipette should not come in contact with any liquid whatsoever.
3. Not recommended. It contradicts statement 1.
4. Recommended. That way the micropipette remains completely vertical, minimizing the risks of being decalibrated.
5. Not recommended. If it lays on the bench it will be horizontal, thus contradicting statement 4.
Answer:
1. A
2. B
3. B
4. A
5. B
Explanation:
Aside from invasives like the crown-of-thorns starfish, what other factor is killing the Great Barrier Reef?
O increased temperatures
O overactive algae
O reactive forms of oxygen
O coral bleaching
Answer:
increased temperatures
Explanation:
The temperatures are increasing in the ocean because of ocean warming, by climate change. The heat in the ocean stresses healthy corals, which drains them of their vibrant colors, known as bleaching.
Which is the correct Lewis structure for acetylene (C2H2)?
Answer:
The answer is H-C≡C-H
Explanation:
Glucose is the monomer in the natural polymers ____________________ and cellulose.
Answer:
Starch
I hope this helps
Please help I’m so confused on this it’s stoichiometry
Answer:
48.27g Na
Explanation:
To start we need to balance the equation. The trick is to make sure both sides have equal amounts of each atom:
2Na + Cl2 --> 2NaCl
Now we can use sociometry
We have 75 g of Cl2, and for every 1 mole of Cl2, there are 70.9 grams:
[tex]75g Cl2 * \frac{1mole Cl2}{70.9g Cl2}= 1.05 mole Cl2[/tex]
Now we have moles of Cl2. To get to grams of Na, we need to first use mole to mole ratio:
[tex]1.05mole Cl2 *\frac{2 mole Na}{1 mole Cl2} =2.1 mole Na[/tex]
From here we convert moles of Na into grams of Na
[tex]2.1mol Na*\frac{22.99g Na}{1 mole Na} = 48.27g Na[/tex]
It's usually easier to just make one singular equation with all of these smaller equations.
[tex]75gNa*\frac{1molCl2}{70.9gCl2} *\frac{2mol Na}{1 mol Cl2} *\frac{22.99g Na}{1 mol Na}=48.27 gNa[/tex]
The trick to sociometry is making sure your units cancel out until you only have the unit you want. If there are moles of Na in the numerator, there needs to be moles of Na in the denominator. If there are grams of Cl2 in the numerator, there needs to be grams of Cl2 in the denominator and so one and so on
Which illustration is a closed circuit? * + A B
Answer:
I believe its B for sure
Hope this helps!
Explanation:
formula for calculating pressure
Answer:
The formula for pressure is P = F/A, in which P is pressure, F is force, and A is area.
Explanation:
6. Which of the process would you use to remove salt
dissolved in water?
opicean .Filtration, evaporation, chlorination
Answer:
Evaporation
Explanation:
You can use evaporation to separate the salt from the water.
The pressure 15.0 m under water is 248 kPa.
What is this pressure in torr
Answer:
1860 torr
Explanation:
In order to convert from kPa to torr, we are going to use the following conversion factor:
1 kPa = 7.5 torrNow we multiply 248 kPa with this factor so that the kPa units cancel each other and only the torr units remain:
248 kPa * [tex]\frac{7.5torr}{1kPa}[/tex] = 1860 torrThis means that the answer is 1860 torr.
kylie jenner wants to test if red or pink lipstick makes her lips look bigger. what is the independent variable here?
Answer:
her ugly duck lips
Explanation:
Answer:
her lips.
Explanation:
the dependent variable is the lip stick because it changes but her lips do not actually change at all, ......i think. ;)
How many grams of sodium (Na) are in 6.2 mol of Na?
mass = mol no. x molar mass
= 6.2 x 23
= 142.6 g
Explain why anhydrous aluminium chloride is fairly soluble in organic solvent while anhydrous magnesium chloride is insoluble
Aluminium chloride is covalent hence soluble in organic solvent while magnesium chloride being ionic is insoluble in organic solvent
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A student determines the molar mass of acetone, CH3COCH3, by the method used in this experiment. She found that the equilibrium temperature of a mixture of ice and water was 1.0 degrees C on her thermometer. When she added 11.1 g of her sample to the mixture, the temperature, after thorough stirring, fell to -3.0 degrees C. She then poured off the solution through a screen into a beaker. The mass of the solution was 90.4 g.a) What was the freezing point depression?b) What was the molality of acetone? I need help especially with this one.c) How much acetone was in the decanted solution?d) How much water is in the decanted solution?e) How much acetone would there be in a solution containing 1 kg of water and acetone at the same concentration as she had in her experiment?f) What did she find to be the molar mass of acetone, assuming she made the calculation properly?
Answer:
(a). 4°C, (b). 2.4M, (c). 11.1 g, (d). 89.01 g, (e). 139.2 g and (f). 58 g/mol.
Explanation:
Without mincing words let's dive straight into the solution to the question.
(a). The freezing point depression can be Determine by subtracting the value of the initial temperature from the final temperature. Therefore;
The freezing point depression = [ 1 - (-3)]° C = 4°C.
(b). The molality can be Determine by using the formula below;
Molality = the number of moles found in the solute/ solvent's weight(kg).
Molality = ( 11.1 / 58) × (1000)/ ( 90.4 - 11.1) = 2.4 M.
(c). The mass of acetone that was in the decanted solution = 11.1 g.
(d). The mass of water that was in the decanted solution = 89.01 g.
(e). 2.4 = x/ 58 × (1000/1000).
x = 2.4 × 58 = 139.2 g.
(f). The molar mass of acetone = (12) + (1 × 3) + 12 + 16 + 12 + (1 x 3) = 58 g/mol.
An antacid tablet with an active ingredient of CaCO3 was dissolved in 50.0 mL of 0.300 M HCl. When this solution was titrated with 0.300 M sodium hydroxide, 32.47 mL was required to reach the end point. Determine the mass (in grams) of calcium carbonate in the tablet. Molar Mass of CaCO3
Answer:
Explanation:
mole of HCl remaining after reaction with CaCO₃
= .3 M of NaOH of 32.47 mL
= .3 x .03247 moles
= .009741 moles
Initial HCl taken = .3 x .005 moles = .0015 moles
Moles of HCl reacted with CaCO₃
= .009741 - .0015 = .008241 moles
CaCO₃ + 2HCl = CaCl₂ + CO₂ + H₂O .
1 mole 2 moles
2 moles of HCl reacts with 1 mole of CaCO₃
.008241 moles of HCl reacts with .5 x .008241 moles of CaCO₃
CaCO₃ reacted with HCl = .5 x .008241 = .00412 moles
the mass (in grams) of calcium carbonate in the tablet
= .00412 x 100 = .412 grams . ( molar mass of calcium carbonate = 100 )
We have that the mass (in grams) of calcium carbonate in the tablet is mathematically given as
mass of CaCO₃= 0.412 grams
The mass (in grams) of calcium carbonate in the tabletQuestion Parameters:
An antacid tablet with an active ingredient of CaCO3 was dissolved in 50.0 mL of 0.300 M HCl. titrated with 0.300 M sodium hydroxide, 32.47 mL was required to reach the end point.Generally the equation for the mole of HCl is mathematically given as
mole of HCl = 0.3 M of NaOH of 32.47 mL
mole of HCl= 0.3 x 0.03247 moles
mole of HCl= 0.009741 moles
Therefore
Initial HCl taken = 0.3 x 0.005 moles
Initial HCl taken= 0.0015 moles
Moles of HCl reacted with CaCO₃
M_{hcl}= 0.009741 - .0015
M_{hcl}= .008241 moles
The Chemical Equation
CaCO₃ + 2HCl = CaCl₂ + CO₂ + H₂O .
Therefore, CaCO₃ reacted with HCl is
CaCO₃ reacted with HCl= 0.5 x 0.008241
CaCO₃ reacted with HCl= .00412 moles
Hence,the mass of CaCO₃ is
mass of CaCO₃ = 0.00412 x 100
mass of CaCO₃= 0.412 grams
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Given that blood exerts the same osmotic pressure as a 0.15 M NaCl solution, which solution could be the hypertonic solution?/search?
a. 0.68 M NaCl solution
b. 0.15 M NaCl solution
c. 0.008 M NaCl solution
Answer:
a. 0.68 M NaCl solution
Explanation:
The tonicity of a solution can either be hypotonic, hypertonic and isotonic. Hypertonic solution is a solution which possesses a higher concentration of solute in relation to another solution.
According to this question, a solution is said to contain 0.15 M NaCl solute. This means that a solution that will be hypertonic to this solution will have a much more concentration of solute, which based on the options provided is the 0.68 M NaCl solution.
What is full ground state electron configuration of C-?
Answer:
[tex]1s^{2}[/tex] [tex]2s^{2}[/tex] [tex]2p^{2}[/tex]
Explanation:
Simply [tex]1s^{2}[/tex] [tex]2s^{2}[/tex] [tex]2p^{2}[/tex]
Coal has two valent electrons, so there is 2 in 2p orbital
Why are invasive species such a huge threat to ecosystems?
Invasive species are impossible to control once they are introduced and spread rapidly
Invasive species can replace native species, forcing their migration out of the area
Invasive species provide no added benefit or diversity to the ecosystem
Invasive species can do intense damage so much so that ecosystems may not be able to recover
Answer: Its D the guy above is wrong dont use his answer he got me a 75
Explanation:
A 50.8g sample of glass, which has a specific heat capacity of 0.670·J·g?1°C?1, is put into a calorimeter (see sketch at right) that contains 150.0g of water. The temperature of the water starts off at 22.0°C. When the temperature of the water stops changing it's 25.6°C. The pressure remains constant at 1atm. Calculate the initial temperature of the glass sample. Be sure your answer is rounded to the correct number of significant digits.
Answer:
Explanation:
mass of glass m = 50.8 g
specific heat s = .67 J /g °C
initial temperature = t
Loss of heat by glass
= m s Δ t
= 50.8 x .67 x ( t - 25.6 )
= 34.036 x ( t - 25.6 )
Gain of heat by water
= 150 x 4.2 x ( 25.6 - 22.0 )
= 2268
Heat gain = heat lost
2268 = 34.036 x ( t - 25.6 )
2268 = 34.036 t - 871.32
34.036 t = 3139.32
t = 92.23°C .
Which of the following are more likely to form a solution? (select all that apply)
A) When both solute and solvent are polar
B) When both solute and solvent are nonpolar
C) When solute is polar and solvent is nonpolar
D) When solute is nonpolar and solvent is polar
Answer:A and B
Explanation:
A substance is said to be polar when it is having a dipole (a delocalised positive and negative charge) or it is ionic (dissociate into ions when dissolved in water)
7. A family used 1,438 kilowatt-hours (kwh) of electricity during the month of
October. Express this amount of energy in joules and Btu. See Appendix A.
Can you please show the steps thanks
Answer:
Im bad at math sorry
Explanation:
What mass of KNO, will dissolve in 100 g of water at 100°C?
Answer:
About 170-180 grams of potassium nitrate are completely dissolved in 100 g.
Explanation:
Hello!
In this case, according to the reported solubility data for potassium nitrate at different temperatures on the attached picture, it is possible to bear out that about 170-180 grams of potassium nitrate are completely dissolved in 100 g; considering that the solubility is the maximum amount of a solute that can be dissolved in a solvent, in this case water.
Best regards!
Which statement best explains how the solution should be made?
A) Add 1.5 mL of 0.50 M H2SO4 to 10.5 mL of water to get 12 mL of 4 M H2SO4.
B) Add 1.5 mL of 4.00 M H2SO4 to 10.5 mL of water to get 12 mL of 0.50 M H2SO4.
C) Add 1.5 mL of 4.00 M H2SO4 to 12 mL of water to get 0.50 M H2SO4.
Answer:
B
Explanation:
Correct on Edge
According to the following reaction, how many grams of carbon tetrachloride will be formed upon the complete reaction of 27.7 grams of chlorine gas with excess carbon disulfide? carbon disulfide (s) + chlorine (g) carbon tetrachloride (l) + sulfur dichloride (s) grams carbon tetrachloride
Answer: 15.0 g of [tex]CCl_4[/tex] will be formed upon the complete reaction of 27.7 grams of chlorine gas with excess carbon disulfide
Explanation:
To calculate the moles :
[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex]
[tex]\text{Moles of} Cl_2=\frac{27.7g}{71g/mol}=0.390moles[/tex]
The balanced chemical reaction is:
[tex]CS_2(g)+4Cl_2(g)\rightarrow CCl_4(l)+2SCl_2(s)[/tex]
[tex]Cl_2[/tex] is the limiting reagent as it limits the formation of product and [tex]CS_2[/tex] is the excess reagent.
According to stoichiometry :
4 moles of [tex]Cl_2[/tex] give= 1 mole of [tex]CCl_4[/tex]
Thus 0.390 moles of will give = [tex]\frac{1}{4}\times 0.390=0.0975moles[/tex] of [tex]CCl_4[/tex]
Mass of [tex]CCl_4=moles\times {\text {Molar mass}}=0.0975\times 154=15.0g[/tex]
Thus 15.0 g of [tex]CCl_4[/tex] will be formed upon the complete reaction of 27.7 grams of chlorine gas with excess carbon disulfide
Convert 75g of NaOH to moles
Answer:
75g and I no inglish I my espanish perfec
Explanation:
Can metals take away electrons from non metals?
Answer:
Well no because if metals lose electrons, any non-metal sources/items gain electrons from the metal.
Answer:
Metals tend to lose electrons and non-metals tend to gain electrons, so in reactions involving these two groups, there is electron transfer from the metal to the non-metal
Explanation:
Write the formulas for the reactants and products. Balance the chemical equation.
Combination/Synthesis Reaction:
Sodium + Oxygen —>
Explanation:
2Na+O2=2N2Ois balanced one
Choose the statement that best describes the effect of temperature on atoms and molecules.
A temperature decrease results in particles having more collisions with other particles
Solids have more kinetic energy than gases.
Decreasing temperature can cause a liquid to become a gas
increases in temperature cause partides to speed up and have more collisions.
Answer:
option D is correct answer of this question
Answer:
Explanation:
As the temperature of a liquid rises, the average speed of its molecules rises as well. The molecules in a liquid move faster as the temperature rises, increasing the liquid's kinetic energy. Heating liquids will demonstrate this property in experiments.
When Earth’s Plates shift the result is a(n)______.
Answer:
An earthquake could occur.
Answer:
The correct answer is (lava)
Explanation:
Youre welcome
When the plates move they collide or spread apart allowing the very hot molten material called lava to escape from the mantle. When collisions occur they produce mountains, deep underwater valleys called trenches, and volcanoes.
Question 4 (4 points)
(01.03 MC)
An energy transformation flow diagram is shown.
X-
ELECTRICAL
ENERGY
What type of energy does X most likely represent? (4 points)
O a
X = gravitational energy
Oь
X = mechanical energy
Ос
= thermal energy
Od
X = radiant energy
Answer:
I think radiant I’m not sure
Explanation:
A balloon is filled with 30L of helium gas at 1atm.What is the volume when balloon rises to an attitude where the pressure is only 0.25 atm?
Answer:
[tex]V_2=120L[/tex]
Explanation:
Hello!
In this case, since Helium is undergoing a volume-pressure change, according the Boyle's law, we infer the following equation is used:
[tex]P_1V_1=P_2V_2[/tex]
Thus, since we are not given the volume at 0.25 atm, we can solve for V2 to do so:
[tex]V_2=\frac{P_1V_1}{P_2}[/tex]
Thus, we plug in to obtain:
[tex]V_2=\frac{1atm*30L}{0.25atm}=120L[/tex]
Best regards!
The final volume of the balloon at the given altitude is 120 L.
The given parameters;
initial volume of the balloon, V₁ = 30 Linitial pressure, P₁ = 1 atmfinal pressure of the balloon, P₂ = 0.25 atmThe final volume of the balloon at the given altitude is calculated by applying Boyles law as follows;
[tex]P_1 V_1 = P_2 V_2\\\\V_2 = \frac{P_1V_1}{P_2} \\\\V_2 = \frac{30 \times 1 }{0.25} \\\\V_2 = 120 \ L[/tex]
Thus, the final volume of the balloon at the given altitude is 120 L.
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what is the mass in grams of 0.687 moles of NH three