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3 years ago

What is the molarity of the following?

1 answer:

7 0

Molarity = number mole of substances/ Volume solution (L)

To find number of mole we need to find Molar mass , at first.

1) M(BaBr2)= M(Ba) +2 M(Br) = 137.3 + 2*80.0= 197.3 g/mol
23g BaBr2 *(1mol BaBr2/197.3 g BaBr2) = 0.12 mol BaBr2
Molarity (BaBr2 solution) =0.12 mol/2.3 L≈0.052 mol/L ( BaBr2 solution)
Molarity of BaBr2 solution = 0.052 M

2) M(CaS)= M(Ca)+M(S)= 40.1+32.1=72.2 g/mol
15 g CaS*(1mol CaS/72.2 g CaS)= 0.21 mol CaS
Molarity (CaS solution) = 0.21 mol/2 L≈ 0.11 mol/L (CaS solution)
Molarity of CaS solution = 0.11 M

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A student combines 20.0 grams of hydrogen and 20.0 grams of oxygen in a reaction. According to the law of conservation of mass,

jekas [21]

Answer:

A)20.0grams

Explanation:

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3 years ago

Read 2 more answers

If 0.092J of heat causes a 0.267 degree C temperature change, what mass of water is present?

Thepotemich [5.8K]

Answer:

0.082g

Explanation:

The following data were obtained from the question:

Heat (Q) = 0.092J

Change in temperature (ΔT) = 0.267°C

Specific heat capacity (C) of water = 4.184J/g°C

Mass (M) =..?

Thus, the mass of present can be obtained as follow:

Q = MCΔT

0.092 = M x 4.184 x 0.267

Divide both side by 4.184 x 0.267

M = 0.092 / (4.184 x 0.267)

M = 0.082g

Therefore, mass of water was present is 0.082.

6 0

3 years ago

he heat of fusion of tetrahydrofuran is . Calculate the change in entropy when of tetrahydrofuran melts at . Be sure your answer

lana [24]

Answer:

$\Delta S=1.8x10^{-3}\frac{kJ}{K}=1.8\frac{J}{K}$

Explanation:

Hello.

In this case, given the heat of fusion of THF to be 8.5 kJ/mol and freezing at -108.5 °C, for the required mass of 5.9 g, we can compute the entropy as:

$\Delta S=\frac{n*\Delta H}{T}$

Whereas n accounts for the moles which are computed below:

$n=5.9g*\frac{1mol}{72g} =0.082mol$

Thus, the entropy turns out:

$\Delta S=\frac{0.0819mol*8.5 kJ/mol}{(-108.5+273.15)K}\\\\\Delta S=1.8x10^{-3}\frac{kJ}{K}=1.8\frac{J}{K}$

Best regards.

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3 years ago

Which of the following radiations consists of a helium nucleus emitted by some radioactive substances? Alpha radiation Beta radi

erica [24]

Answer: Alpha radiation

Explanation: Alpha decay : When a larger radioactive nuclei decays into smaller nuclei by releasing alpha radiation, the mass number and atomic number is reduced by 4 and 2 units respectively.

$_Z^A\textrm{X}\rightarrow _{Z-2}^{A-4}Y+_2^4\textrm{He}$