1. Un átomo de volframio (W) tiene 74 protones y 108 neutrones. ¿Cuál es su representación adecuada?

When do the highest tides happen?

mart [117]

Answer:

A) When the moon is full

Explanation:

The moon controls the tides, so the more the moon the more the tide

8 0

2 years ago

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The three major groups on the peridoic table are the ____

qaws [65]

Metals on the left side, metalloids on the staircase, nonmetals on right side

5 0

3 years ago

During a 4 hour trip, a boat sailed 70 km in 2 h. Then the boat did not move for 1 hour and traveled 26 km in the last hour. Wha

Lubov Fominskaja [6]

Answer:

32km/hr

Explanation:

The question asks to calculate the average speed for a boat.

Mathematically, the average speed is the total distance divided by the total time

Let’s get the total distance traveled:

That would be 70km + 26km = 96km

Now the total time taken would be 3 as the boat did not move at all for an hour.

The average speed is thus 96/3 = 32km/hr

7 0

3 years ago

A 1.0 L volume of gas at 27.0°C exerts a pressure of 85.5 K PA what will the pressure be at 127°C assume constant volume

Marianna [84]

Answer:

114 kPa

Explanation:

Using Gay-Lussac's law you get the equation $\frac{P1}{T1} x \frac{P2}{T2}$ and converting celcius you get the final equation of $\frac{85.5}{27+273} x \frac{P2}{127+273}$ . After dividing 85.5 by 27+273(300) you get 0.285 and then you multiply 0.285 by 127+273 (400). You finally get 114 kPa

4 0

2 years ago

Methanol, ethanol, and n−propanol are three common alcohols. When 1.00 g of each of these alcohols is burned in air, heat is lib

KengaRu [80]

Answer:

For methanol: Heat of combustion = -22.6 kJ / 0.0312 moles = -724.3590 kJ/mol (negative sign signifies release of heat)

For ethanol: Heat of combustion = -29.7 kJ / 0.0217 moles = -1368.6636 kJ/mol (negative sign signifies release of heat)

For propanol: Heat of combustion = -33.4 kJ / 0.0166 moles = -2012.0482 kJ/mol (negative sign signifies release of heat)

Explanation:

Given:

Mass of Methanol = 1.0 g

Mass of ethanol = 1.00 g

Mass of n-propanol = 1.00 g

For methanol:

2 CH₃OH + 3 O₂ ----> 2 CO₂ + 4 H₂O, ∆H₀ = -22.6 kJ/g (negative sign signifies release of heat)

1 g of methanol on combustion gives 22.6 kJ of energy

Calculation of moles of methanol:

$moles=\frac{Mass(m)}{Molar\ mass (M)}$

Molar mass of methanol = 32.04 g/mol

Thus moles of methanol = 1 g/ (32.04 g/mol) = 0.0312 moles

Hence energy in kJ/mol:

Heat of combustion = -22.6 kJ / 0.0312 moles = -724.3590 kJ/mol (negative sign signifies release of heat)

For ethanol:

C₂H₅OH + 3 O₂ ----> 2 CO₂ + 3 H₂O, ∆H₀ = -29.7 kJ/g (negative sign signifies release of heat)

1 g of ethanol on combustion gives 29.7 kJ of energy

Calculation of moles of ethanol:

$moles=\frac{Mass(m)}{Molar\ mass (M)}$

Molar mass of ethanol = 46.07 g/mol

Thus moles of ethanol = 1 g/ (46.07 g/mol) = 0.0217 moles

Hence energy in kJ/mol:

Heat of combustion = -29.7 kJ / 0.0217 moles = -1368.6636 kJ/mol (negative sign signifies release of heat)

For propanol:

2 C₃H₇OH + 9 O₂ ----> 6 CO₂ + 8 H₂O, ∆H₀ = -33.4 kJ/g , (negative sign signifies release of heat)

1 g of methanol on combustion gives 33.4 kJ of energy

Calculation of moles of methanol:

$moles=\frac{Mass(m)}{Molar\ mass (M)}$

Molar mass of methanol = 60.09 g/mol

Thus moles of methanol = 1 g/ (60.09 g/mol) = 0.0166 moles

Hence energy in kJ/mol:

Heat of combustion = -33.4 kJ / 0.0166 moles = -2012.0482 kJ/mol (negative sign signifies release of heat)

5 0

3 years ago