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4 years ago

At STP, a 7.49-gram sample of an element has a volume of 1.65 cubic centimeters. The sample is most likely

1 answer:

6 0

You can identify an element by its density.
$\rho = \frac{m}{V}$
ρ - density, m - mass, V - volume

$m=7.49 \ g \\
V=1.65 \ cm^3 \\ \\
\rho=\frac{7.49 \ g}{1.65 \ cm^3} \approx 4.54 \ \frac{g}{cm^3}$

It's the density of titanium (Ti). The answer is (4).

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Describe the method of steel manufacture used when removes the impurities carbon, phosphorus and sulfur

melisa1 [442]

Explanation:

Steelmaking is the process of producing steel from iron ore and/or scrap. In steelmaking, impurities such as nitrogen, silicon, phosphorus, sulfur and excess carbon (most important impurity) are removed from the sourced iron, and alloying elements such as manganese, nickel, chromium, carbon and vanadium are added to produce different grades of steel.

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6 0

3 years ago

How many grams of CuF2 are needed to make a 2.8 M solution

11111nata11111 [884]

Molarity is given as,

Molarity = Moles / Volume of Solution ----- (1)

Also, Moles is given as,

Moles = Mass / M.mass

Substituting value of moles in eq. 1,

Molarity = Mass / M.mass × Volume

Solving for Mass,

Mass = Molarity × M.mass × Volume ---- (2)

Data Given;

Molarity = 2.8 mol.L⁻¹

M.mass = 101.5 g.mol⁻¹

Volume = 1 L (I have assumed it because it is not given)

Putting values in eq. 2,

Mass = 2.8 mol.L⁻¹ × 101.5 g.mol⁻¹ × 1 L

Mass = 284.2 g of CuF₂

5 0

3 years ago

When humans burn fossil fuels, most of the carbon quickly enters the_______

Len [333]

Answer:

Atmosphere.

Explanation:

Carbon moves from fossil fuels to the atmosphere when fuels are burned. When humans burn fossil fuels to power factories, power plants, cars and trucks, most of the carbon quickly enters the atmosphere as carbon dioxide gas.

8 0

3 years ago

Read 2 more answers

Calculate the standard reaction enthalpy for the reaction NO2(g) → NO(g) + O(g) given +142.7 kJ/mol for the standard enthalpy of

bulgar [2K]

Answer:

The standard reaction enthalpy for the given reaction is 235.15 kJ/mol.

Explanation:

$O_2(g) \rightarrow \frac{2}{3}O_3(g),\Delta H^o_{1}=142.7 kJ/mol$ ..[1]

$O_2(g) \rightarrow 2 O(g),\Delta H^o_{2}=498.4 kJ/mol$ ..[2]

$NO(g) + O_3(g)\rightarrow NO_2(g) + O_2(g) ,\Delta H^o_{3} = -200 kJ/mol$ ..[3]

$NO_2(g)\rightarrow NO(g) + O(g),\Delta H^o_{4}=?$ ..[4]

Using Hess's law:

Hess’s law of constant heat summation states that the amount of heat absorbed or evolved in a given chemical equation remains the same whether the process occurs in one step or several steps.

2 × [4] = [2]- (3 ) × [1] - (2) × [3]

$2\times \Delta H^o_{4}=\Delta H^o_{2} -3\times \Delta H^o_{1}-2\times \Delta H^o_{3}$

$2\times \Delta H^o_{4}=498.4 kJ/mol-3\times 142.7 kJ/mol-2\times -200 kJ/mol$

$2\times \Delta H^o_{4}=470.3 kJ/mol$

$\Delta H^o_{4}=\frac{470.3 kJ/mol}{2}=235.15 kJ/mol$

The standard reaction enthalpy for the given reaction is 235.15 kJ/mol.

7 0

3 years ago

50.0 ml of 0.010m naoh was titrated with 0.50m hcl using a dropper pipet. if the average drop from the pipet has a volume of 0.0

creativ13 [48]

25 drops of acid is required to neutralize the 50.0 ml of 0.010m of NaOH in the experiment.

The equation of the reaction is;

NaOH(aq) + HCl(aq) ---------> NaCl(aq) + H2O(l)

We can use the titration formula;

CAVA/CBVB = NA/NB

CA= concentration of acid

VA = volume of acid

CB = concentration of base

VB = volume of base

NA = number of moles of acid

NB = number of moles of base

CB = 0.010 M

VB = 50.0 ml

CA = 0.50 M

VA = ?

NA = 1

NB = 1

Substituting values;

CAVANB = CBVBNA

VA = 0.010 × 50.0 × 1/ 0.50 × 1

VA = 1 ml

Since the total volume of acid used is 1 ml and each drop contains 0.040 ml

The number of drops required is 1ml/0.040 ml = 25 drops

Learn more: brainly.com/question/1527403

4 0

3 years ago