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3 years ago

Which pattern(s) may be observed from the arrangement of elements in the periodic table? Select all that apply.

1 answer:

6 0

It’s organized by the atomic number which is the protons so the answer is A although they can be organized through groups and periods if valance electrons are included

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I NEED HELPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPP

pav-90 [236]

Answer:

Explanation:

4 0

3 years ago

Read 2 more answers

Based on the equation, how many grams of Br2 are required to react completely with 42.3 grams of AlCl3? AlCl3 + Br2 → AlBr3 + Cl

rusak2 [61]

Answer:

76.1 grams.

Explanation:

From the balanced reaction:

2AlCl₃ + 3Br₂ → 2AlBr₃ + 3Cl₂,

2.0 moles of AlCl₃ reacts with 3.0 moles of Br₂ to produce 2.0 moles of AlBr₃ and 3.0 moles of Cl₂.

We need to calculate the no. of moles of (42.3 g) of AlCl₃:

no. of moles of AlCl₃ = mass/molar mass = (42.3 g)/(133.34 g/mol) = 0.3172 mol.

Using cross multiplication:

2.0 moles of AlCl₃ react completely with → 3.0 moles of Br₂.

0.3172 mol of AlCl₃ react completely with → ??? moles of Br₂.

∴ The no. of moles of Br₂ = (0.3172 mol)(3.0 mol)/(2.0 mol) = 0.4759 mol.

∴ The amount of grams of Br₂ are required to react completely with 42.3 grams of AlCl₃ = (no. of moles of Br₂)(molar mass) = (0.4759 mol)(159.81 g/mol) = 76.05 g ≅ 76.1 g.

4 0

3 years ago

Two objects are brought into contact Object 1 has mass 0.76 kg, specific heat capacity 0.87) g'c and initial temperature 52.2 'C

taurus [48]

Answer:

$T_F=77.4\°C$

Explanation:

Hello there!

In this case, according to the given information, it turns out possible to set up the following energy equation for both objects 1 and 2:

$Q_1=-Q_2$

In terms of mass, specific heat and temperature change is:

$m_1C_1(T_F-T_1)=-m_2C_2(T_F-T_2)$

Now, solve for the final temperature, as follows:

$T_F=\frac{m_1C_1T_1+m_2C_2T_2}{m_1C_1+m_2C_2}$

Then, plug in the masses, specific heat and temperatures to obtain:

$T_F=\frac{760g*0.87\frac{J}{g\°C} *52.2\°C+70.7g*3.071\frac{J}{g\°C}*154\°C}{760g*0.87\frac{J}{g\°C} +70.7g*3.071\frac{J}{g\°C}} \\\\T_F=77.4\°C$

Yet, the values do not seem to have been given correctly in the problem, so it'll be convenient for you to recheck them.

Regards!

4 0

3 years ago

Kon kon rajasthan ka h

xenn [34]

Answer:

I am from Pakistan

Explanation:

Nice to meet you!

8 0

3 years ago

f 65mL of sulfuric acid and 25mL of sodium hydroxide were mixed and the solution had a density of 1.01g/mL, what is the heat of

user100 [1]

The question is incomplete, here is the complete question:

If 65 mL of sulfuric acid and 25 mL of sodium hydroxide were mixed and the solution had a density of 1.01 g/mL, What is the heat of the calorimeter in kJ given the temperature change of the above equation is -5.5 K. You may assume the solution has a heat capacity of 4.180 J/gK. Express your final answer in kJ and with 2 decimal places

Answer: The heat of the calorimeter is 2.09 kJ

Explanation:

To calculate the mass of solution, we use the equation:

$\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}$

Density of solution = 1.01 g/mL

Volume of solution = [65 + 25] mL = 90 mL

Putting values in above equation, we get:

$1.01g/mL=\frac{\text{Mass of solution}}{90mL}\\\\\text{Mass of solution}=(1.01g/mL\times 90mL)=90.9g$

To calculate the heat released by the reaction, we use the equation:

$q=mc\Delta T$

where,

q = heat released

m = mass of solution = 90.9 g

c = heat capacity of solution = 4.180 J/g.K

$\Delta T$ = change in temperature = -5.5 K

Putting values in above equation, we get:

$q=90.9g\times 4.180J/g.K\times (-5.5K)=-2089.8J=-2.09kJ$

Heat released by the solution will be equal to the heat absorbed by the calorimeter.

Sign convention of heat:

When heat is absorbed, the sign of heat is taken to be positive and when heat is released, the sign of heat is taken to be negative.

Heat absorbed by the calorimeter = -(-2.09) = 2.09 kJ

Hence, the heat of the calorimeter is 2.09 kJ

8 0

4 years ago