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Phoenix [80]
3 years ago
9

How many moles does 205g of helium, He contains ?

Chemistry
2 answers:
Ne4ueva [31]3 years ago
7 0
<span>Moles = weight in g / atomic weight So, moles in 40 g of He = 40 / 4 = 10 moles.</span>
Travka [436]3 years ago
7 0
19.512 
i hope this helps

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Write balanced nuclear equations for the following:(a) β⁻ decay of silicon-32
S_A_V [24]

The balanced nuclear equations for the following:(a) β⁻ decay of silicon-32 is (27,14)Si -> (0,-1)beta + (27,15)P

<h3>What is balanced nuclear equation?</h3>

A nuclear reaction is generally expressed by a nuclear equation, which has the general form, where T is the target nucleus, B is the bombarding particle, R is the residual product nucleus, and E is the ejected particle, and Ai and Zi (where I = 1, 2, 3, 4) are the mass number and atomic number, respectively. Finding a well balanced equation is critical for understanding nuclear reactions. Balanced nuclear equations provide excellent information about the energy released in nuclear reactions. Balancing the nuclear equation requires equating the total atomic number as well as the total mass number before and after the reaction using the rules of atomic number and mass number conservation in a nuclear reaction.

To learn more about nuclear equations visit:

brainly.com/question/12221598

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7 0
2 years ago
Can yall plz help me it’s a huge major grade and i don’t know how to do this
fomenos

Answer:

1. 48 mols

2. 0.2 M

5. 1.25 L

Explanation:

Molarity= mols divided by liters

Hope this helps not sure about 3 and 4

3 0
4 years ago
In a 1.0-liter container there are, at equilibrium, 0.10 mole h2, 0.20 mole n2, and 0.40 mole nh3. what is the value of kc for t
bogdanovich [222]
The reaction involved here would be written as:

2N2 + 3H2 = 2NH3

The equilibrium constant of a reaction is the ratio of the concentrations of the products and the reactants when in equilibrium. The expression for the equilibrium constant of this reaction would be as follows:

Kc = [NH3]^2 / [N2]^2[H2]^3
Kc = 0.40^2 / (0.20)^2 (0.10)^3 
Kc = 4000
6 0
3 years ago
describe in general terms an experiment to determine the molal freezing point depression constant kf of water. Assume the availa
Dvinal [7]
A solution (in this experiment solution of NaNO₃) freezes at a lower temperature than does the pure solvent (deionized water). The higher the solute concentration (sodium nitrate), freezing point depression of the solution will be greater.
Equation describing the change in freezing point: 
ΔT = Kf · b · i.
ΔT - temperature change from pure solvent to solution.
Kf - the molal freezing point depression constant.
b -  molality (moles of solute per kilogram of solvent).
i - Van’t Hoff Factor.
First measure freezing point of pure solvent (deionized water). Than make solutions of NaNO₃ with different molality and measure separately their freezing points. Use equation to calculate Kf.

6 0
3 years ago
What is the percent composition by mass of oxygen in Ca(NO3)2 (gram-formula= 164 g/mol)?
Neko [114]
To find this, we will use this formula:

Molar mass of element
------------------------------------ x 100
Molar mass of compound

So, first lets calculate the mass of the compound as a whole. We use the atomic masses on the periodic table to determine this.

Ca: 40.078 g/mol
N2 (there is two nitrogens): 28.014 g/mol
O6 (there are six nitrogens: 3 times 2): 95.994 g/mol

When we add all of those numbers up together, we get 164.086. That is the molar mass for the whole compound. However, we are trying to figure out what percent of the compound oxygen makes up. From the molar mass, we know that 95.994 of the 164.086 is oxygen. Lets plug those numbers into our equation!

95.994
-----------
164.086

When we divide those two numbers, we get .585. When we multiply that by 100, we get 58.5.

So, the percent compostition of oxygen in Ca(NO3)2, or, calcium nitrate, is 58.5%.
5 0
3 years ago
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