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3 years ago

Which of the following elements has the most properties in common with iron (Fe)?

2 answers:

8 0

If my memory serves me well, the following element which has the most properties in common with iron (Fe) is definitely <span>Osmium (Os) because they are stand for the same group!
I'm sure it helps!</span>

Luda [366]3 years ago

8 0

Answer:

Osmium

Explanation:

Got it right on the test.

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7.00 of Compound x with molecular formula C3H4 are burned in a constant-pressure calorimeter containing 35.00kg of water at 25c.

beks73 [17]

Answer:

$\Delta H_{f,C_3H_4}=276.8kJ/mol$

Explanation:

Hello!

In this case, since the equation we use to model the heat exchange into the calorimeter and compute the heat of reaction is:

$\Delta H_{rxn} =- m_wC_w\Delta T$

We plug in the mass of water, temperature change and specific heat to obtain:

$\Delta H_{rxn} =- (35000g)(4.184\frac{J}{g\°C} )(2.316\°C)\\\\\Delta H_{rxn}=-339.16kJ$

Now, this enthalpy of reaction corresponds to the combustion of propyne:

$C_3H_4+4O_2\rightarrow 3CO_2+2H_2O$

Whose enthalpy change involves the enthalpies of formation of propyne, carbon dioxide and water, considering that of propyne is the target:

$\Delta H_{rxn}=3\Delta H_{f,CO_2}+2\Delta H_{f,H_2O}-\Delta H_{f,C_3H_4}$

However, the enthalpy of reaction should be expressed in kJ per moles of C3H4, so we divide by the appropriate moles in 7.00 g of this compound:

$\Delta H_{rxn} =-339.16kJ*\frac{1}{7.00g}*\frac{40.06g}{1mol}=-1940.9kJ/mol$

Now, we solve for the enthalpy of formation of C3H4 as shown below:

$\Delta H_{f,C_3H_4}=3\Delta H_{f,CO_2}+2\Delta H_{f,H_2O}-\Delta H_{rxn}$

So we plug in to obtain (enthalpies of formation of CO2 and H2O are found on NIST data base):

$\Delta H_{f,C_3H_4}=3(-393.5kJ/mol)+2(-241.8kJ/mol)-(-1940.9kJ/mol)\\\\\Delta H_{f,C_3H_4}=276.8kJ/mol$

Best regards!

7 0

3 years ago

If your lawn is 21.0 ft wide and 20.0 ft long, and each square foot of lawn accumulates 1350 new snow flakes every minute. How m

klemol [59]

Let us start with the total area of the lawn. Area= width x length, ie, 21 x 20 = 420 sq. ft. Snow flakes per square foot per minute = 1350 So Snow flakes for 420 sq.feet per minute = 420 x 1350 = 567000. Snow flakes for 1 hour = 567000 x 60 = 34020000 (60 minutes) Weight of 34020000 snow flakes = 34020000 x 1.60 = 54432000mg. To convert it into kilograms, divide this number by 1000000 (1 kilogram = 1000000 milligrams) Thus 54432000/1000000 = 54.432 kilograms or 54 kilograms and 432 grams.

6 0

3 years ago

Molarity is measured in

aniked [119]

Answer D moles per L

5 0

3 years ago

Hydrogen peroxide decomposes to form water and oxygen gas according to the following equation: 2H2O2(aq)  2H2O(l) + O2(g) If 31

olya-2409 [2.1K]

Answer:

141.89 dm^3

Explanation:

The equation of the reaction is;

2H2O2(aq) --------->2H2O(l) + O2(g)

Now , we are told that the mass of hydrogen peroxide decomposed was 315g. Number of moles of hydrogen peroxide in 315g of the substance is given by;

Number of moles= mass/molar mass

Molar mass of hydrogen peroxide= 34.0147 g/mol

Number of moles= 315g/34.0147 g/mol = 9.26 moles of hydrogen hydrogen peroxide.

From the reaction equation;

2 moles of hydrogen peroxide yields 1 mole of oxygen

9.26 moles of hydrogen peroxide yields 9.26 ×1/2 = 4.63 moles of oxygen

From the ideal gas equation;

Volume of the gas V= the unknown

Pressure of the gas P= 0.792 atm

Temperature of the gas= 23°C +273 = 296 K

Number of moles of oxygen = 4.63 moles of oxygen

R= 0.082atmdm^3K-1mol-1

Hence, from PV=nRT

V= nRT/P

V= 4.63 × 0.082 × 296/0.792 = 141.89 dm^3

8 0

3 years ago

Methane (CH4) reacts with water (H20) to produce carbon monoxide (CO) and hydrogen (H2)

lilavasa [31]

This reaction only occurs at high temperatures and in the presence of a metal-based catalyst (nickel). And the H2O is in the form of steam (due to the high temperature)

7 0

3 years ago