New quizz EMerald 2020

What should be the value of distance d so that final image is formed on the object itself. (Focal lengths of the lenses are written on the lenses):

A plastic bottle contains 0.6 g of N2(g).

Another bottle of the same size is filled at the same temperature and pressure with an unknown gas. If the mass of second gas is 1.52 g, this gas can be :

From the following data :

C(s) + 2H2(g) → CH4(g)            ΔH = – 75kJ/mol

3C(s) + 4H2(g) → C3H8(g)        ΔH = – 100kJ/mol

What is ΔH for transformation?

3CH4(g) → C3H8(g) + 2H2(g)

The following complete reaction is realized:

N₂ (g)+ 3 H₂ (g) ⟶ 2 NH₃ (g)using 0.5 mol of N₂ (g) and 2.5 mol of H₂ (g).

Under normal conditions of temperature and pressure, what is the volume occupied by the system at the end of the reaction?

Which mass of NaI(s) should you dissolve in 50mL water to obtain a solution of 0.2mol/L in NaI ?

(answer in g)

I’ve got a 2 mol/l aqueous solution of hydrogen chloride. I take 5 mL of it and dilute it with water to a final volume of 100 mL. The final concentration of hydrogen chloride in the resulting solution is:

What is the mass of 3.2 moles of ammonium nitrate (NH₄NO₃)? (answer in g)

What is the molar weight of potassium chloride?

The mass of 250mL of liquid benzene is 220g, what is the density if this liquid?

The charge of a capacitor of 1 μF in a discharging RC circuit decreases by a factor of 2 in 10 milliseconds. Calculate its resistance (write just the number).

The power required to ensure a flow rate Q of water in the following two-pipe system is 0.5

W. (η_water = 1.10^-3 Pas )

Knowing ΔP= 10Pa between A and B, calculate the flow: (answer in m³/s)

A ball is thrown from the ground with a velocity of 10 m/s following an angle of 30° from the horizontal to a vertical wall, located at 2 m.

How high will it hit the wall? (answer in meter)

Consider the following homogeneous beam of mass m supported by a cable.

Knowing that the beam is in equilibrium, calculate the tension in the cable and the mass m of the beam.

( answer m = ….kg,  tension = … N)

A solution of 0.05M MIBC needs to be prepared from a solution of 100ml of MIBC at 0.1M. How much water should be added in order to obtain this diluted solution?

(answer in mL)

Mark the appropriate geological events associated with the kind of boundaries shown in the following figure.

What is represented in the figure below?

Which of the following relationships are true?

“Reporting tonnages of an orebody is a complex task as it directly depends on the delineation of ore boundaries. Any mistakes in identification of boundaries can lead to either misidentification of an orebody or totally ignoring a big part of it. The number of drill holes increases the degree of confidence on the information about the presence of mineralization. Also, overlooking the geological features like fault or folds may lead to discontinuities in the mineralization which might lead to erroneous tonnage estimations”

What could be the possible reasons of uncertainties in identification of a continuous ore body (marked in pink in the figure)?

“Reporting tonnages of an orebody is a complex task as it directly depends on the delineation of ore boundaries. Any mistakes in identification of boundaries can lead to either misidentification of an orebody or totally ignoring a big part of it. The number of drill holes increases the degree of confidence on the information about the presence of mineralization. Also, overlooking the geological features like fault or folds may lead to discontinuities in the mineralization which might lead to erroneous tonnage estimations”

If no mineralization is found in the pink area by additional drilling campaigns. Mark all the possible factors which might be responsible for it?

If 6 underground loaders need 6 minutes to load 6 Mtons of ore on the conveyor system, how many of them are needed to load 80 Mtons of ore in 48 minutes? (write just the number)

Solve this equation:

Solve this equation:

The keyboard of a machine has 42 keys, including 8 numbers and 26 letters. The keys are typed randomly.

Knowing that the keys are equiprobable, calculate the probability of typing a sequence of 5 letters. (write just the number)

There is a family of 5 children, for each of them, the probability of being a boy or a girl is 1/2.

The probability of having exactly 2 boys and 3 girls in the family is ……. (write just the number)

Consider an Oxy marker in which the coordinates of points B, C and E are B (0, 4), C (3.5, 5), E (5, 0). All position data are in centimeters.

Determine the area of the hexagon defined in the figure below where the angles O, B, C and E are 145°, 150°, 110° and 120° respectively.

(write just the number)

Knowing the following distances, calculate the area of the quadrangle Brussels-Berlin-Athen-Lisboa:

Bruxelles-Berlin : 648km

Bruxelles –Lisbon : 1713km

Bruxelles-Roma : 1182 km

Bruxelles-Athen : 2089km

Lisbon-Berlin : 2310km

Lisbon-Roma :1873km

Berlin-Athen : 1801km

(write just the number of km²)

The temperature in a laboratory rose 6 degrees Celsius, which represents half of the previous temperature. What is the current temperature? (write just the number)

“A rhyolitic tuff from Nevada (USA) containing 1 g / ton is valuable today given the price of gold and average operating costs in large scale mining operations”.

According to today’s gold price (41.21 €/g) what should be the maximum limit of production cost/ton of ore to maintain the gold grade profitable?

“A rhyolitic tuff from Nevada (USA) containing 1 g / ton is valuable today given the price of gold and average operating costs in large scale mining operations”.

Which of the following inferences cannot be drawn from the statement presented above?

In an iron ore mine, one of the processing plants is currently fed with 200t/h of ore to produce 160t/h of hematite concentrate at 68% Fe grade. A study to improve the plant’s efficiency showed that the increase of 2 flotation cells in the rougher stage of flotation could improve the plant recovery in 4% with a small decrease of 1% in Fe grade. If the market currently pays 120€ per ton of Fe in the concentrate, what would be the hourly increase in revenue obtained by installing these 2 cells? Note: do not consider any additional operational or installation costs.

(answer in EUR/h)

Sedimentary rocks could form upon weathering, erosion, sedimentation and lithification of_________

A deposit with a grade of 2.5% Zn and with an ore body of density 2.5 g.cm3, will be mined by open pit method. The dimension of the open pit will be 200 m depth, 100 m width and 300 m length.

How many tonnes of Zinc can be extracted? (write just the number)