id stringlengths 2 7 | question stringlengths 12 991 | answer stringlengths 1 1.1k | answer_type stringclasses 11
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|---|---|---|---|---|---|
1423090 | An aqueous solution contains {eq}\displaystyle \rm 0.32 \ M
{/eq} ammonia. One liter of this solution could be converted into a buffer by the addition of (Assume that the volume remains constant as each substance is added.)
(a) {eq}\displaystyle \rm 0.33 \ mol \ NH_4Br
{/eq}
(b) {eq}\displaystyle \rm 0.32 \ mol \ ... | d | Multiple Choice | Biology-Chemistry | Senior High School |
609242 | Fill in the blank:
The condition of an animal cell when placed into a hypertonic solution is called _____. | crenation | String | Biology-Chemistry | Senior High School |
1979584 | If you wanted to prove that DNA but not RNA synthesis was preceding, what radioactive compound would you see? | Radioactive titrated thymidine | String | Biology-Chemistry | University |
998270 | 1.09 g #H_2# is allowed to react with 10.2 g #N_2#, producing 1.12 g #NH_3#. What is the theoretical yield in grams for this reaction under the given conditions? | Dihydrogen is the limiting reagent, and at most we can make \(2/3\) equiv ammonia. | Float | Biology-Chemistry | Senior High School |
757822 | Iodine-131 is a radioactive isotope. After 7.00 days, 54.7% of a sample of 131I remains. What is the half-life of 131I? | 8.04 days | Float | Biology-Chemistry | Senior High School |
562754 | According to the following reaction, how many grams of water are necessary to form 0.767 moles of zinc hydroxide?
zinc oxide (s) + water (l) {eq}\to
{/eq} zinc hydroxide (aq) | 13.8 g of H2O | Float | Biology-Chemistry | Senior High School |
1076816 | A solution of {eq}HNO_3{/eq} is standardized by reaction with pure sodium carbonate. {eq}2H^+ + Na_2CO_3 \rightarrow 2Na^+ + H_2O + CO_2{/eq}
A volume of 28.28+-0.05 mL of {eq}HNO_3{/eq} solution was required for complete reaction with 0.8711+-0.0007g of {eq}Na_2CO_3{/eq} (FM 105.988+-0.001). Find the molarity of the ... | 0.581 M +- 0.001 M | Float | Biology-Chemistry | University |
1301574 | True or false? Hybrid orbitals exist in isolated atoms. | false | Boolean | Biology-Chemistry | Senior High School |
975691 | NaCl has a #DeltaH_(fus)# = 30.2 kJ/mol. What is the mass of a sample of NaCl that needs 732.6 kJ of heat to melt completely? | 559 g Na | String | Biology-Chemistry | Senior High School |
1097540 | The {eq}K_{sp}
{/eq} of {eq}Sn_3(BO_3)_4
{/eq} is 6.128 x {eq}10^{-12}
{/eq}. Determine the molar solubility. | 0.007 M | Float | Biology-Chemistry | Senior High School |
1670968 | What is the volume of 4.37 moles of an ideal gas at {eq}26.5^{\circ}C
{/eq} and 1.00 atm? | 107.38 L | Float | Biology-Chemistry | Senior High School |
1302332 | A mixture initially contains A, B, and C in the following concentrations: A = 0.650 M , B = 0.950 M , and C = 0.500 M . The following reaction occurs and equilibrium is established: A+2B<=>C At equilibrium, A = 0.480 M and C = 0.670 M . Calculate the value of the equilibrium constant, Kc. Express your answer numericall... | 3.75 | Float | Biology-Chemistry | Senior High School |
1759722 | What is the pH of {eq}1.0 \times 10^{-9}
{/eq} M HCIO{eq}_4
{/eq}(aq)?
a. 1.0
b. 5.0
c. 7.0
d. 9.0
e. none of these | c | Multiple Choice | Biology-Chemistry | Senior High School |
499136 | Calculate the total heat released when heating 36.0 g of ice (water) at -15 degree Celsius up to the melting point, 110 degree Celsius.
ΔH of vaporization = 40.7 kj/mol
specific heat capacity of water = 4.18 j/mol.C
specific heat capacity of solid = 2.09 j/mol.C
ΔH of fusion = 6.02kj/mol. | 95070.1 J | Float | Biology-Chemistry | Senior High School |
994968 | Write the equilibrium constant expression for the following reaction:
{eq}\displaystyle \rm NH_4I (s) \rightleftharpoons NH_3 (g) + HI (g)
{/eq} | {eq}K_{eq} = \left[ {N{H_3}} \right]\left[ {HI} \right]{/eq} | Expression | Biology-Chemistry | Senior High School |
234486 | Calculate the enthalpy change per mole of oxygen consumed in the reaction:
2U(s) + 3O2(g) → 2UO3(s). | -815.7 kJ/mol O2 | Float | Biology-Chemistry | Senior High School |
12315 | A rock contains 0.257 mg of Pb-206 for every 1.0 mg of U-238. The half-life for the decay of U-238 to Pb-206 is {eq}4.5 \times 10^9
{/eq} years. How old is the rock? | 1.5 billion years | Float | Biology-Chemistry | Senior High School |
512720 | A neuroepithelium is an example of which epithelial tissue function? | sensory | String | Biology-Chemistry | Senior High School |
882476 | What is the concentration of {eq}\displaystyle
15.0 mL
{/eq} of potassium hydroxide needed to neutralize {eq}\displaystyle
10.0 mL
{/eq} of hydrochloric acid with a concentration of {eq}\displaystyle
0.8 M?
{/eq} | 0.5 M | Float | Biology-Chemistry | Senior High School |
1354900 | Suppose a 500 mL flask is filled with 2.0 mol of {eq}H_2
{/eq} and 1.9 mol of {eq}HCl
{/eq}. The following reaction becomes possible:
$$H_2 (g) + Cl_2(g) \rightleftharpoons 2HCl (g)
$$
The equilibrium constant K for this reaction is 0.774 at the temperature of the flask.
Calculate the equilibrium molarity o... | 2.38 M | Float | Biology-Chemistry | University |
858268 | What are the steps that 1-pentyne goes through to become N-ethyl pentanamide? | 1. Convert 1-pentyne to pentanal using H2SO4 and HgSO4 at 60°C.
2. Oxidize pentanal to pentanoic acid using KMnO4.
3. React pentanoic acid with ethylamine and heat to produce N-ethyl pentanamide. | List | Biology-Chemistry | University |
140891 | Identify the Resonance Hybrid
a. CH_3 CH = CH - CH_2
b. CH_3 CH = CH - CH - CH = CH_2
c. CH_3 CH - CH = CH - CH = CH_2
d. CH_3 CH - CH - CH - CH_2
e. CH_3 CH = CH - CH = CH - CH_2
CH_3 CH = CH - CH - CH = CH_2 and
CH_3 CH - CH = CH - CH = CH_2 | c | Multiple Choice | Biology-Chemistry | Senior High School |
308613 | Blood serum in healthy adults normally contains approximately 3.2 mg/mL of sodium ions ({eq}Na^+
{/eq}) and approximately 3.5 mg/mL of chloride ions ({eq}Cl^-
{/eq}). How many milliliters of blood serum would be needed to obtain 3.1 grams of {eq}Na^+
{/eq}? | 968.8 mL | Float | Biology-Chemistry | Senior High School |
446099 | Write the equilibrium constant expression {eq}K_p
{/eq} for the following reaction: {eq}\rm 2NO + Br_2 \rightleftharpoons 2NOBr
{/eq}. | {eq}K_p = \frac{p_{NOBr}^2}{P_{NO}^2\cdot p_{Br_2}}{/eq} | Expression | Biology-Chemistry | Senior High School |
1391103 | The molar mass of organic acid was determined by the following study of its barium salt.
4.290 g of the salt were to be converted to the free acid by reaction with 21.64 mL of 0.477 M {eq}H_2SO_4
{/eq}.
The barium salt was known to contain 2 moles of water of hydration per mol {eq}Ba^{2+}
{/eq}, and the acid was kn... | 122.14 g/mol | Float | Biology-Chemistry | University |
722688 | The chlorofluorocarbon {eq}\rm{CCl}_2F_2
{/eq} was once used as a refrigerant. What mass of this substance must evaporate to freeze {eq}2\ \rm{mol}
{/eq} water initially at {eq}20^\circ \rm{C}
{/eq}? ({eq}\Delta H_{vap}
{/eq} for {eq}\rm{CCl}_2F_2
{/eq} is {eq}289\ \rm{J/g}
{/eq}; {eq}\Delta H_{fus}
{/eq} for so... | 52.1 g | Float | Biology-Chemistry | Senior High School |
1929661 | What is the duct that connects to the duodenum? | There are three ducts that connect to the duodenum:
1. Common Bile Duct
2. Pancreatic Duct
3. Accessory Pancreatic Duct | List | Biology-Chemistry | Senior High School |
1825025 | Consider the following data showing the initial rate of a reaction (A → products) at several different concentrations of A. What is the order of the reaction?
[A](M)
Initial Rate (M/s)
0.15
0.011
0.30
0.022
0.60
0.045 | 1 | Integer | Biology-Chemistry | Senior High School |
1065278 | Calculate the mass (in grams) of {eq}4.25 \times 10^{3}
{/eq} moles of iron. | 237341.25 g | Float | Biology-Chemistry | Senior High School |
57773 | A piece of sodium metal completely reacts in water as follows:
{eq}\rm
\displaystyle 2Na(s) + 2H_2O(l) \rightleftharpoons 2NaOH(aq) + H_2(g)
{/eq}
The hydrogen gas generated is collected over water at {eq}\rm
25 ^\circ C
{/eq}. The volume of the gas is 231 mL measured at 1.00 atm. Calculate the number of grams of... | 0.4341 g | Float | Biology-Chemistry | Senior High School |
1446675 | When 2.25 g of sodium hydroxide (NaOH) was dissolved in 100.00 g of water, a value of 10.50 {eq}^o
{/eq}C was obtained for ΔT. Calculate the value (calories) for the heat solution of 2.25 g of NaOH. | 1073.63 cal | Float | Biology-Chemistry | Senior High School |
471105 | Write a balanced chemical equation for the breakdown of selenious acid {eq}\rm H_2SeO_3
{/eq} in water. | H_{2}SeO_{3} \rightarrow 2H^{+} + SeO_{3}^{2-} | Expression | Biology-Chemistry | Senior High School |
1568549 | How much nitrogen is required to fully consume 11.0 g of hydrogen? | 51.33 g | Float | Biology-Chemistry | Senior High School |
2032720 | Iron ore is 36.0% FeO by mass. How many grams of Fe are contained in 875 grams of ore? | 245 g | Integer | Biology-Chemistry | Senior High School |
677061 | HCIO is a weak acid {eq}(K_a = 4.0 \times 10^-8)
{/eq}and so the salt NaCIO acts as a weak base. What is the pH of a solution that is 0.037 M in NaCIO at 25 degree C | 10 | Integer | Biology-Chemistry | Senior High School |
1959520 | Calculate the pH when 45.0 mL of a 0.378 M solution of a monoprotic weak acid, {eq}HA
{/eq}, is mixed with 45.0 mL of a 0.378 M sodium hydroxide solution at 25 degrees Celsius. For {eq}HA
{/eq}, the {eq}K_a
{/eq} is {eq}2.9 \times 10^{-5}
{/eq}. | 8.9 | Float | Biology-Chemistry | University |
1458050 | Consider the following reaction: {eq}2H_2O(l) \leftrightharpoons 2H_2(g) + O_2(g); K_c = 7.3 \times 10^{-18}
{/eq} at 1000 degrees Celsius. The initial concentration of water in a reaction vessel is 0.055 mol/L. What is the equilibrium concentration of {eq}H_2(g)
{/eq} at 1000 degrees Celsius? | 3.6e-7 M | Float | Biology-Chemistry | Senior High School |
877712 | The adrenal cortex produces the hormones ________. | Cortisol and Aldosterone | List | Biology-Chemistry | Senior High School |
144133 | What is the tissue type for the following structure of the heart?
Sinus/veins | The coronary veins and coronary sinus have three layers: tunica intima (inner layer, epithelial tissue), tunica media (middle layer, smooth muscle tissue), and tunica adventitia (outer layer, connective tissue). | List | Biology-Chemistry | Senior High School |
1730204 | Given the following information, determine the Keq for the following reaction:
2H2S (g) ↔ 2H2(g) + S2(g)
Substance
Concentration (M) at equilibrium
H2S
0.15
H2
0.010
S2
0.051 | 2.267e-4 | Float | Biology-Chemistry | Senior High School |
1686880 | The action of bacteria on meat and fish results in cadaverine, a compound which is also present in bad breath and adds to the odor of urine. Cadaverine is 58.77% carbon, 13.81% hydrogen, and the remainder is nitrogen. What is the empirical formula for cadaverine? | C5H14N2 | String | Biology-Chemistry | Senior High School |
173681 | 5 mg iodine(131) has a half life of 8.1 days.
What is the time when 1% remain? | 54.153 days | Float | Biology-Chemistry | Senior High School |
1879744 | The neurotransmitter briefly 'binds to' receptors on axon number _____. | postsynaptic neuron | String | Biology-Chemistry | Senior High School |
661733 | How many chromium atoms are in 0.00442 moles of chromium? | 2.6e+21 atoms | Float | Biology-Chemistry | Senior High School |
1223144 | Balance the chemical equation.
{eq}\rm
\displaystyle B_2S_3 + H_2O \to H_3BO_3 + H_2S
{/eq} | B2S3 + 6H2O -> 2H3BO3 + 3H2S | Expression | Biology-Chemistry | Senior High School |
839510 | There is a correlation between algae height and the snout-to-vent length of a group of marine iguanas in the galapagos. what may be causing the change in size of marine iguanas on different islands? | Island area | Other | Biology-Chemistry | Senior High School |
2100511 | In the male reproductive system, the _____ secrete(s) a fluid that neutralizes acidic conditions in the vagina. | Bulbourethral Glands | String | Biology-Chemistry | Senior High School |
1587244 | How much salt, NaCl, is in the average adult human body?
a. 2 kilograms
b. 1 kilogram
c. 500 grams
d. 250 grams | d | Multiple Choice | Biology-Chemistry | Senior High School |
1334260 | A certain second-order reaction required 60.2 seconds for the concentration to drop from 0.50 M to 0.36 M. How long will it take (in seconds) for the sample to go through three half-lives (starting from 0.50 M)? | 465.09 s | Float | Biology-Chemistry | Senior High School |
616921 | For the reaction I_2(g) + Cl_2(g) <--> 2 ICl(g) @ 25^o C, K_p = 81.9. If the initial partial pressures are all 0.100 atm, find the equilibrium concentrations | At the equilibrium, the pressure of I_2 and the pressure of Cl_2 are equal to 0.028 atm. The pressure of ICl is 0.2464 atm. | Float | Biology-Chemistry | Senior High School |
81156 | Calculate the solubility of solid calcium phosphate ({eq}ksp = 1.3 \times 10^{-32}
{/eq}) in a 0.20 M Sodium Phosphate solution. | 2.29e-11 | Float | Biology-Chemistry | University |
628538 | The fictitious compound, pandemonium carbonate, Pn(CO_3)_2 has a Ksp = 3.091 x 10^{-9} M^3 in water at room temperature. Calculate the solubility of Pn(CO_3)_2 in an aqueous solution of 1.11 M pandemonium sulfate, Pn(SO_4)_2 (aq). Express your answer in units of molarity. | 627.18e-12 M | Float | Biology-Chemistry | University |
1925318 | What is the theoretical yield (in grams) of ethanol from the fermentation of 79.5 grams of glucose?
{eq}C_6H_{12}O_6 \to 2CH_3CH_2OH + 2CO_2
{/eq} | 40.6 grams | Float | Biology-Chemistry | Senior High School |
317514 | Which branch of biology makes the most use of mathematics? | Computational biology, biostatistics, and bioinformatics | List | Biology-Chemistry | Senior High School |
1840848 | What mass of water is produced from the complete combustion of {eq}7.30 \times 10^{-3}
{/eq} grams of methane? | 0.016 g | Float | Biology-Chemistry | Senior High School |
1842943 | Draw Lewis structures for the following compounds/ions. In which of the compounds/ions listed is the octet rule impossible to satisfy for all atoms in the formula?
{eq}A.\ PCl_5\\
B.\ ICl_3\\
C.\ XeF_4\\
D.\ NO_2\\
E.\ OF_3\\
F.\ CO_3^{2-}
{/eq} | NO_2 | String | Biology-Chemistry | Senior High School |
1200779 | How many atoms are present in 22.0 grams of {eq}Mg(OH)_2
{/eq}? | 11.5e23 atoms | Float | Biology-Chemistry | Senior High School |
85626 | Find the pH of {eq}\rm 1.0 \times 10^{-8}\ M\ KOH
{/eq} solution. | 7.04 | Float | Biology-Chemistry | Senior High School |
1761442 | Robin the Research scientist prepares 100 ml of a solution of 100 mM of Tris HCl. What is the pH of the solution? | 4.53 | Float | Biology-Chemistry | University |
956014 | What is the density of methane, {eq}CH_4
{/eq}, in a vessel where the pressure is {eq}910
{/eq} torr and the temperature is {eq}255 \ K
{/eq}? | 0.915 g/L | Float | Biology-Chemistry | Senior High School |
1741354 | For the reaction below, identify the reduction half-reaction:
$$\text {Fe} + \text V_2\text O_3 \rightarrow \text {Fe}_2\text O_3 + \text {VO}
$$ | V^(6+) + 4e^- -> V^(2+) | Expression | Biology-Chemistry | Senior High School |
853690 | Determine the volume of KOH required to reach a pH of 4.20 for the titration of 50.00 mL of 0.100 M benzoic acid {eq}(K_{\text{a}} = 6.3 \times 10^{-5})
{/eq} with 0.0500 M KOH. | 50.0 mL | Float | Biology-Chemistry | University |
1340233 | Given their size and complexity, biological molecules such as carbohydrates, proteins, lipids, and nucleic acids can also be referred to as ____________. | Macromolecules | String | Biology-Chemistry | Senior High School |
1260543 | For a buffer solution containing {eq}\displaystyle \rm 0.15 \ M
{/eq} of {eq}\displaystyle \rm NH_4Cl
{/eq} and {eq}\displaystyle \rm 0.035 \ M \ NH_3
{/eq}, the pH equals {eq}\displaystyle \rm 8.62
{/eq} and for the {eq}\displaystyle \rm NH_3
{/eq} the {eq}\displaystyle \rm K_b
{/eq} equals {eq}\displaystyle \rm... | -0.04 | Float | Biology-Chemistry | Senior High School |
351048 | Write the ground state electron configuration of {eq}\rm Br
{/eq} using the noble-gas shorthand notation. | [Ar]4s^23d^104p^5 | String | Biology-Chemistry | Senior High School |
1774936 | In the laboratory, a general chemistry student measured the pH of a 0.552 M aqueous solution of hydrofluoric acid to be 1.685. Use the information she obtained to determine the Ka for this acid.
Ka(experiment) = | 8.03e-4 | Float | Biology-Chemistry | Senior High School |
2097961 | Which of the listed reactions evolve a combustible gas...? | B | Multiple Choice | Biology-Chemistry | Senior High School |
1723236 | What is the largest unit of DNA organization? | genome | String | Biology-Chemistry | Senior High School |
1505225 | The equilibrium constant, {eq}K_c
{/eq}, for the following reaction is 6.30 at 723 K. Calculate {eq}K_p
{/eq} for this reaction at this temperature.
{eq}2NH_3(g) \leftrightharpoons N_2(g) + 3H_2(g)
{/eq} | 22198.74 atm^2 | Float | Biology-Chemistry | Senior High School |
1383863 | 1.04 g {eq}H_2 \text{ reacts with 10.2 g } N_2 \text{ producing 2.71 g } NH_3
{/eq}, what is the theoretical yield in grams? | 5.90 g | Float | Biology-Chemistry | Senior High School |
1849963 | Find the maximum value of H{eq}_2
{/eq}(g) in grams that would be expected to form by reacting 6.54 g of zinc with 50 mL of 0.1 M HCl. | 5 mg | Integer | Biology-Chemistry | Senior High School |
1097702 | Your cotton candy experiment was run in a calorimeter with 455 mL of water that started at 18.7 {eq}^{\circ}
{/eq}C. After combusing 2.44 g of cotton candy, the temperature of the water was measured at 35.1 {eq}^{\circ}
{/eq}C. Find the heat absorbed by the water, {eq}q_{water}
{/eq}. | 31.2 kJ | Float | Biology-Chemistry | Senior High School |
1174405 | Does everyone get posterior vitreous detachment? | No | Boolean | Biology-Chemistry | Senior High School |
1520179 | A tank contains 1000 litres of water with 15 kilograms of salt dissolved in it. Pure salt enters the tank at the rate of 10 litres per minute. The solution is kept thoroughly mixed and drains from the tank at the rate of 10 litres per minute. What is the quantity of salt left in the tank after 20 minutes? | 193.55 kg | Float | Biology-Chemistry | Senior High School |
2075953 | A certain reaction has an activation energy of 44.80 kJ/mol. At what Kelvin temperature will the reaction proceed 4.50 times faster than it did at 319 K? | 350 K | Integer | Biology-Chemistry | Senior High School |
1246776 | A buffer solution is formed by adding 0.200 moles of solid potassium nitrite, {eq}KNO_2
{/eq}, to 500.0 ml of 0.500 M nitrous acid, {eq}HNO_2
{/eq}, solution. You may assume that the change in volume is negligible upon addition of the solid.
Calculate the pH of the buffer solution after the addition of 5.00 mL of 4.... | 2.967 | Float | Biology-Chemistry | University |
1495557 | _____ are involved in transfer of genetic information from one bacterial cell to another.
A) Flagella
B) Cilia
C) Pili
D) Ribosomes
E) Plasmids | C | Multiple Choice | Biology-Chemistry | Senior High School |
831436 | Calculate the pH of a mixture that is formed by adding 55.0 mL of {eq}1.5 \times 10^{-2}
{/eq} M {eq}HCl
{/eq} to 150 mL of {eq}1.0 \times 10^{-2}
{/eq} M {eq}HI
{/eq}. | 1.945 | Float | Biology-Chemistry | Senior High School |
583358 | Equal volumes of 1 M solutions of citric acid, sodium citrate, sodium hydrogencitrate, and sodium dihydrogencitrate are combined and the mu H is adjusted to 9.5 using 1 M NaOH. What is/are the major species (other than H_2O) in the solution? | sodium citrate | String | Biology-Chemistry | University |
1578469 | Evidence from which type of data supports the common origin of all life on Earth? | Genetic Data | String | Biology-Chemistry | Senior High School |
1177109 | Write the K expression for the following equation.
{eq}\rm
Ti (s) + 2 Cl_2 (g) \rightleftarrows TiCl_4 (l)
{/eq} | K = \frac{1}{[Cl_2]^2} | Expression | Biology-Chemistry | Senior High School |
2098873 | Suppose that a fully charged lead-acid battery contains 1.50 L of 5.00 M {eq}\rm
H_2SO_4
{/eq}. What will be the concentration of {eq}\rm
H_2SO_4
{/eq} in the battery after 3.20 A of current is drawn from the battery for 9.00 hours? | 4.64 M | Float | Biology-Chemistry | Senior High School |
755038 | A weak base has a Kb of 7.90*10^-7. What concentration of this base will produce a pH of 10.01? | 0.0133 M | Float | Biology-Chemistry | Senior High School |
96682 | Automobile airbags contain solid sodium azide, {eq}NaN_3
{/eq}, that reacts to produce nitrogen gas when heated, thus inflating the bag.
{eq}2NaN_3(s) \to 2Na(s) + 3N_2(g)
{/eq}
Calculate the value of work, {eq}w
{/eq}, for the system if 22.9 grams of {eq}NaN_3
{/eq} reacts completely at 1.00 atm and 22 degrees C... | 1296.96 J | Float | Biology-Chemistry | Senior High School |
1258579 | From the concentrations given, calculate {eq}K_{sp}
{/eq} for the slightly soluble solid.
{eq}CaCO_3: [Ca^{2+} ] =5.3 \times 10^{-3} \ M, [CO_3^{2-} ] = 9.0 \times 10^{-7} \ M
{/eq} | 4.8e-9 | Float | Biology-Chemistry | Senior High School |
1884661 | Name the compound {eq}\rm (CH_3)_2CHCCCH_3
{/eq}. | 4-Methlpent-2-yne | String | Biology-Chemistry | Senior High School |
1728210 | Use the Henderson-Hasselbalch equation to calculate the pH of a solution that is 0.105 M in {eq}HC_2H_3O_2
{/eq} and 0.125 M in {eq}KC_2H_3O_2
{/eq}. | 4.830 | Float | Biology-Chemistry | University |
1758857 | Calculate the value of the equilibrium constant {eq}(K_c)
{/eq} for the reaction shown, if {eq}\rm NO_2(g)
{/eq} was found to be {eq}95.54 \%
{/eq} decomposed at {eq}45.00 ^\circ C
{/eq} when its initial concentration was {eq}\rm 5.725\ mol/L
{/eq}. The initial concentration of the reaction products is {eq}\rm 0\ ... | 42.1M^{-1} | Float | Biology-Chemistry | Senior High School |
769798 | Calculate the concentrations of all species present in a 0.63 M {eq}NH_3
{/eq} solution. {eq}(K_b = 1.8 \times 10^{-5})
{/eq} | [NH_4^+] = [OH^-] = 0.00336 M, [NH_3] = 0.60M, [H^+] = 3.0e-12M | List | Biology-Chemistry | Senior High School |
11713 | Toxic Cr(VI) can be precipitated from an aqueous solution by bubbling SO{eq}_2{/eq} through the solution. How many grams of SO{eq}_2{/eq} are required to treat 3.00 x 10{eq}^8{/eq} L of 0.0400 mM Cr(VI)?
{eq}\rm 2 CrO_4^2- + 3SO_2 + 4H^+ \rightarrow Cr_2(SO_4)_3 + 2H_2O
{/eq} | 1.15e6 grams | Float | Biology-Chemistry | University |
1080491 | A gas has a density of 3.17 g/L at 49 degrees Celsius and 0.939 atm. Calculate the molar mass of the gas, assuming it obeys the ideal gas law. | 89.29 g/mol | Float | Biology-Chemistry | Senior High School |
1911094 | Balance the following equation: {eq}IBr + NH_3 \to NI_3 + NH_4Br
{/eq} | 3IBr + 4NH_3 → NI_3 + 3NH_4Br | Expression | Biology-Chemistry | Senior High School |
1575039 | From the data recorded in the table below, calculate the pressure that would be observed.
$$\begin{matrix}
\text{temperature} & 21.5^\circ \text{C}\\
\text{moles } H_2 &\\
\text{volume } & 125.0 \text{ mL }\\
\end{matrix}
$$ | 193.52n | Expression | Biology-Chemistry | Senior High School |
2034068 | What is the largest buret that will deliver 4.8mL with an accuracy of at least 0.5%? | 100-mL buret | String | Biology-Chemistry | Senior High School |
20048 | What are the solute particles present in aqueous solution of acetic acid? | Ethanoate ion, hydronium ion, and undissociated ethanoic acid molecules | List | Biology-Chemistry | Senior High School |
1616935 | Given the reaction between ammonia and oxygen as {eq}4NH_3 + 5O_2 \to 4NO + 6H_2O
{/eq}, calculate the amount of nitrogen monoxide (in grams) produced if 0.5 grams of ammonia is reacted with 0.5 grams of oxygen. Indicate what the limiting reactant is. | 0.4 g NO, oxygen is the limiting reactant | String | Biology-Chemistry | Senior High School |
2056910 | Carbon dioxide, which is recognized as the major contributor to global warming as a "greenhouse gas", is formed when fossil fuels are combusted, as in electrical power plants fueled by coal, oil, or natural gas. One potential way to reduce the amount of {eq}CO_2
{/eq} added to the atmosphere is to store it as a compre... | 3.48e9 L | Float | Biology-Chemistry | Senior High School |
2044157 | A 3.46-liter sample of gas was collected over water on a day when the temperature was 21{eq}{^{\circ}}
{/eq}C and the barometric pressure was 718 torr. The dry sample of gas had a mass of 4.20 g. What is the molecular weight of the gas? | 31.01 grams/mole | Float | Biology-Chemistry | Senior High School |
1234842 | Metallic zinc reacts with aqueous {eq}\displaystyle \rm HCl
{/eq}.
{eq}\displaystyle \rm Zn(s) + 2 HCl(aq) \to ZnCl_2(aq) + H_2(g)
{/eq}
What volume of {eq}\displaystyle \rm 2.60 \ M \ HCl
{/eq}, in milliliters, is required to convert {eq}\displaystyle \rm 12.6 \ g
{/eq} of {eq}\displaystyle \rm Zn
{/eq} complet... | 149 mL | Integer | Biology-Chemistry | Senior High School |
664211 | If the symbol {eq}X
{/eq} represents a central atom, {eq}Y
{/eq} represents outer atoms, and {eq}Z
{/eq} represents lone pairs on the central atom, identify the molecular geometry of the molecule with the formula {eq}XY_4Z
{/eq}. | Trigonal pyramidal | String | Biology-Chemistry | Senior High School |
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