胡雪8°

what is the height of the building if the 1st angle of elevation is 50 degrees & the 2nd is 28 degrees were taken at distance 100 feet apart?

The synthesis of ammonia from nitrogen and hydrogen is reversible and exothermic: _N2 + _H2 <--> ¬_NH3?

College Algebra...Quadratic equations...help!?

At a certain temperature, the Kp for the decomposition of H2S is 0.814 atm. EASY 10 PTS?

Activation energy = ___ kJ/mol?

請問一下1000 ppm的HCl中 Cl離子有幾ppm?

請問folin試劑的分子量多少，我看到有94也有260多?

Probability with Replacement help!?

Help with the first maths question pls? I got 3/4.?

Electricity: Electric Circuits please show work~?

calculate the wavelength of the Lyman line of the hydrogen spectrum in which yhe innitial quantum number,n is 5.?

Chemistry Question. Please Help?

Chemistry Question?

What will be Kc for the reaction between A and B?

What is the oxidation number of N in NH4(H2PO4)?

Math question: What is the maximum value and when does it occur?

Chemistry Help?

Chemistry question?

Casey can peel k apples in 10 minutes. In terms of k, how many apples can casey peel in m minutes. In terms of k how many minutes to peel 1?

A 100-g aluminum calorimeter contains 500 g of water at a temperature of 20ºC.?

what would be the word equation for " 2Na3PO4 + 3MgCl2 == 6NaCI + Mg3(PO4)2?

Help why an a concentration of FeSCN^2+ can be assumed to be equal to that of the initial SCN- concentration.?

What is the pH of a solution containing 1.396 mol L-1 of a weak acid with pKA = 8.39 a?

What is the pH of a solution containing 1.396 mol L-1 of a weak acid with pKA = 8.39 and 0.506 mol L-1 of another weak acid with pKA = 4.70?

Calculate the equilibrium concentration of H2O in the second mixture at this temperature.?

Consider a weak base "B". What is the pH of a 0.118 mol L-1 solution of B? The KB of B is 5.14 x 10-7?

Chemistry question?

Calculate the volume of each gas sample at STP: 23.2 mol Cl2, 4.6 mol nitrogen, 3.2 mol helium, 29 mol CH4? (Liters)?

CHEMISTRY CONCENTRATION NEUTRALISATION?

TITRATION QUESTION?

Math: How to find h in the picture?

What is the specific heat (SH) of the substance?

Chem 20 help please!?

Write the net ionic equation for the hydrolysis of hydrocyanic acid, HCN(aq)?

first order rate law decomposition?

A 25.07 g sample of a substance is initially at 23.8 °C.?

The rate laws for the thermal and photochemical decomposition of NO2 are different.?

Calculate the equilibrium concentration of B2(g) in a vessel that initially contains 1.00 M AB(g). 2AB(g) <--> A2(g) + B2(g) kc=4.0a?

What is the electronic configuration for the following elements? Zn: Na+:?

Chemistry, How would you approach 3?

A sample of oxygen gas occupies a volume of 350 cm3 at 840 torr pressure. What volume will it occupy at 900 torr pressure?

0.9775 grams of an unknow compound is dissolved in 50.0 mL of water. Initially, the water temperature is 22.3degree C.?

Help please?

What is the pH of a 0.417 M solution of hypobromous acid (HBrO)? Ka = 2.8 ✕ 10^-9?

What type of particle is present in a sample of aluminum chloride (AlCl3)?

Solve math question?

Solve. ​ log6x+log6(x−1)=1 ​?

pre calculus?

Calculate the frequency of a photon of this radiation (in hertz).?

If the density of water at 29 oC is 0.9959 g cm-3, what is the mass of 10.00 mL of water in grams?