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dexar [7]
3 years ago
12

1. What is a half-life?

Chemistry
1 answer:
irina [24]3 years ago
3 0
<h2>Answer:</h2>

<h2>Half-life, in radioactivity, the interval of time required for one-half of the atomic nuclei of a radioactive sample to decay (change spontaneously into other nuclear species by emitting particles and energy), or, equivalently, the time interval required for the number of disintegrations per second of a radioactive ..!!</h2><h2 /><h2 />

<h2>Hopefully u will satisfy with my answer..!!</h2><h2>Please Mark on brainleast please..!!</h2>

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Calcium carbide reacts with water to produce acetylene gas according to the following equation: CaC2(s) + 2H2O(l)C2H2(g) + Ca(OH
gtnhenbr [62]

Answer: The number of moles of CaC_2 reacted was 0.229

Explanation:

According to ideal gas equation:

PV=nRT

P = pressure of gas = Total pressure - vapor pressure of water = (749 - 23.8) mm Hg= 725.2 mm Hg = 0.954 atm    (760mmHg= 1atm)

V = Volume of gas = 5.87 L

n = number of moles = ?

R = gas constant =0.0821Latm/Kmol

T =temperature =25^0C=(25+273)K=298K

n=\frac{PV}{RT}

n=\frac{0.954atm\times 5.87L}{0.0821 L atm/K mol\times 298K}=0.229moles

CaC_2(s)+2H_2O(l)\rightarrow C_2H_2(g)+Ca(OH)_2(aq)

According to stoichiometry:

1 mole of C_2H_2 is produced by = 1 mole of CaC_2

Thus 0.229 moles of C_2H_2 is produced by = \frac{1}{1}\times 0.229=0.229 moles of CaC_2

Thus number of moles of CaC_2 reacted was 0.229

5 0
3 years ago
At this pressure, how many molecules of air would there be in a 20 ∘C experimental chamber with a volume of 0.020 m3 ?
jonny [76]

Answer:

Explanation: The lowest pressure in a laboratory is 4.0×10^-11Pa

Using Ideal gas equation

PV = nRT

P= 4.0×10^-11Pa

V= 0.020m^3

T= 20+273= 293k

n=number of moles = m/A

Where m is the number of molecules and A is the Avogradro's number=6.02×10²³/mol

R=8.314J/(mol × K)

PV= m/A(RT)

4.0×10^-11 ×0.020 = m/6.02×10²³(8.314×293)

m = 4.0×10^-11×0.020×6.02×10^23 / (8.314×293)

m = 1.98×10^8 molecules

Therefore,the number of molecules is 1.98×10^8

8 0
3 years ago
In terms of shape and volume, how can a gas be defined ?
Gnoma [55]

Particles in a gas are far apart compared to a solid or liquid, allowing it not to have a definitive shape or volume. This also means that gases can fill any container and be easily compressed.

4 0
3 years ago
How many milliliters of 4.00 m hcl(aq) are required to react with 2.75 g of zn(s)?
Anna007 [38]
25 milliliters are required
7 0
3 years ago
How many moles of nitrogen, N, are in 76.0 g of nitrous oxide, N2O?
guapka [62]
If the balanced equation reads:

2N2 + O2 ———> 2N2O

You should have 1.72 moles of N2.
8 0
3 years ago
Read 2 more answers
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