300 Answered Questions for the topic chem


What Volume of a 0.53 M HCl solution is required to neutralize 16.5 mL of a .124 M Ca(OH)2 Solution?

What Volume of a 0.53 M HCl solution is required to neutralize 16.5 mL of a .124 M Ca(OH)2 Solution?


What is the mass of 3.01 x 10²² molecules of carbon dioxide at STP?

using dimensional analysis


What volume, in liters, at STP, is occupied by 3.30 X 10²³ molecules of oxygen gas?

using dimensional analysis


calculating mass/volume at STP

1) What is the mass of 75.0 L of methane gas (CH₄) measured at STP?2) What volume, in liters, will be occupied by 48.8 g of helium gas at STP?3) What volume, in liters, at STP, is occupied by 3.30... more


buffer system equilibrium

5. A buffered system of HC2H3O2/NaC2H3O2 by combining 20.0 mL of 0.60 M HC2H3O2 and 20.0 mL of 0.60 M NaC2H3O2. The Ka of HC2H3O2 is 1.80x10-5, pKa = 4.74.


Acid/Base equilibrium calculations

How many mol of solid LiA would have to be added to 1.0 L of a 3.726 M HA solution in order to obtain a buffer of 2.99? (The Ka for HA is 5.92⋅10−6).
Chem Chemistry


Which statement is correct and explain

The standard reduction potential for halogens are given belowHalogens Standard Reduction Potential at 25 oC I2(s) + 2 e– → 2 I–(aq) +0.535Br2(l) + 2 e– → 2 Br–(aq) ... more
Chem Chemistry


Need help w/Chemistry question about titrations and pH!

A volume of 25.0 mL of 0.100 M CH3CO2H(aq) is titrated with 0.100 M NaOH(aq). What is the pH after the addition of 12.5 mL of NaOH? Ka for CH3CO2H = 1.8e10-5

Satisfying Octet Rule?

Draw Lewis structures for the following compounds/ions.Decide if the compound/ion listed can satisfy the octet rule (duet rule for H), if so choose Satisfies Octet Rule from the drop down menu.If... more

Finding Bond Polarity?

Rank the following bonds from least polar to most polar:Ge−FF−FK−FSe−FAs−Fleast polar  ______<  _____ < _____<  ______<  ______  most polar

Finding the Identity of an Unknown Ion

An unknown ion with a charge of +1 has the following electron configuration:[Ar] 4s0 3d5 4p5What is the identity of the unknown ion?

Finding the Excited State?

A hydrogen atom in an excited state returns to the ground state. The photon emitted in this process has a wavelength of 122 nm. What was the excited state of the hydrogen atom prior to returning to... more


Finding Frequency?

Part 1You have 0.100 mol of H atoms in the ground state. How much energy is required to transition all of the atoms from the ground state to n=5?1.26×105 JPart 2What is the frequency of the light... more

Chemistry question about solutions

Why do we use salt on ice in cold weather? The combination increases the boiling point of the ice, making it melt faster. The combination increases the vapor pressure of the ice, so it evaporates... more

(Please Help) Determination of boiling point of unknown liquid

Data:Calibration of thermometer:In ice-water system:Actual temperature, T(°C): T1: 0.0Thermometer reading, R(°C): R1 :0.2In boiling water system:Actual temperature, T(°C): T2: 100.0Thermometer... more

Finding partial pressure at equilibrium?

One method for producing hydrogen is to react coke (mostly solid carbon) with steam to make syngas, a mixture of CO and hydrogenC(s) + H2O(g) ⇌ CO(g) + H2(g)     Kp = 0.45 at 900 K     ΔH = +131... more

Finding the Average Epsilon and Molarity of Unknown Solution

Stock Solution: 8.8×10-5 MSolution #1: 1.809×10-5 MSolution #2: 1.046×10-5 MYou measure the absorbance of each solution (at λmax = 524 nm) and obtain the following results: ... more

Heat of Formation for One Mole

Find the heat of formation for a mole of carbon monoxide (CO) given: CO2(g) + C(s) → 2CO(g) ∆ Ho = 172.5 kJ C(s) + O2(g) → CO2(g) ∆ Ho = -393.5 kJ Use kJ and 3 significant figures for... more

Finding Reactants and Using a Balanced Equation

Ammonia is produced from the reaction of nitrogen and hydrogen according to the following balanced equation:N2(g) + 3H2(g) → 2NH3(g)1. What is the maximum mass of ammonia that can be produced from... more

Theoretical yield of CO2 produced by combustion

Assuming gasoline is 90.0% isooctane, with a density of 0.692 g/mL, what is the theoretical yield (in grams) of CO2 produced by the combustion of 1.10 x 1010 gallons of gasoline (the estimated... more

Finding "Mystery Elements" by using the isotope format

I am really confused on numbers 3 and 4 of the chart because of their use of charges. I think number three is Titanium and four is Chlorine, but cannot figure out the electrons or neutrons. Enter... more

Fill in the blank for protons, neutrons, electrons, and charge

Fill in the blanks in the chart below with the symbol, mass number, number of protons, neutrons and electrons and charge. When you enter the charges, enter them after the number, i.e. 2+ or... more


A gas has a density of 0.791 g/L. What is the molar mass of this gas?

I wonder why the formula is m (mass) = p x V (density multiply with volume)But the answer key of the book is: Molar Mass (M) = g/L × 22.4 L/1 mole = p x VSO , in this situation , do we find mass =... more

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