Which type of investigation is based on observation?

Always carry the microscope with________________-one on the ____________ and one underneath the____________ of the microscope

Ronch [10]

Answer:

Always carry the microscope with two hands. One on the arm and one underneath the base of the microscope.

5 0

3 years ago

SI unit for measuring distance is

MrMuchimi

The SI unit for measuring distance is the meter.
I attached a table of SI measurements for you :)
Hope this helped!

6 0

3 years ago

Aqueous hydrobromic acid (HBr) reacts with solid sodium hydroxide (NaOH) to produce aqueous sodium bromide (NaBr) and liquid wat

Alexxandr [17]

Answer: park with the green green yellow green orange green green brown green orange orange green orange yellow orange orange brown orange orange yellow orange

Explanation:

3 0

3 years ago

Commercially available aqueous nitric acid has a density of 1.42 g/mL and a concentration of 16 M. Calculate the mass percent of

luda_lava [24]

Answer:

The mass % of HNO3 in the solution is 71.0 %

Explanation:

Step 1: Data given

Density of HNO3 = 1.42 g/mL

Concentration = 16 M = 16 mol /L

Molar mass HNO3 = 63.01 g/mol

Assume the volume = 1L or 1000 mL

Step 2: Calculate mass of the solution

Mass = density * volume

Mass = 1.42 g/mL * 1000 mL

Mass = 1420 grams

Step 3: Calculate moles HNO3

Moles = molarity * volume

Moles = 16 M * 1L

Moles = 16 moles

Step 4: Calculate mass HNO3

Mass HNO3 = moles * molar mass

Mass HNO3 = 16.0 moles * 63.01 g/mol

Mass HNO3 = 1008.16 grams

Step 5: Calculate the mass percent

mass % = (1008.16 grams / 1420 grams) *100%

mass % = 71.0 %

The mass % of HNO3 in the solution is 71.0 %

5 0

3 years ago

Consider 2.4 moles of a gas contained in a 4.0 L bulb at a constant temperature of 32°C. This bulb is connected to an evacuated

Luden [163]

Complete Question

The complete question is shown on the first uploaded image

Answer

a

As the valve is opened , the gas will flow into the empty container until the both containers have the same pressure

b

$\Delta H = 0\ , \Delta E = 0 , q= 0 , w= 0$

c

The driving force for this process is the increase in entropy this is because the movement of the internal energy of the gas into a larger volume, what this does is that it increases the amount of disorder(entropy).

Explanation

In order to obtain the parameter in the part B of the question we are first obtain the initial pressure, using the ideal gas equation

$P = \frac{nRT}{V}$

$P = \frac{(2.4mol)(0.0821\frac{1 atm}{K \cdot \ mol} )}{4.0L}$

$P =15 \ atm$

The next thing is to obtain the new pressure of the gas , using boyle's law

$P_1V_1 = P_2V_2$

$P_2 = \frac{P_1 V_1}{V_2}$

$P_2 = \frac{(15 \ atm)(4.0L)}{24.0 L}$

$P_2 = 2.5 \ atm$

Since the this process is isothermal , the change in heat is equal to zero

i.e q = 0 J

The workdone to move the gas to the other container is zero because the the pressure at this second container is zero due to the fact that it is a vacuum

i.e $w = -P_{external} \Delta V$

$=-(0 \ atm) (24.0 - 4.0L)$

$= 0L \cdot atm$

Since the change in heat is zero and the workdone is zero then the change in internal energy is equal to 0

This is because the change in internal energy is equal to a summation of change in heat and the workdone

i.e $\Delta E = q + w$

$= 0J$

Generally the change in enthalpy is mathematically represented as

$\Delta H = n C_p \Delta T$

Since the temperature is zero this means that the change in temperature is zero , substituting this value for change in temperature into the equation for change in enthalpy

$\Delta H = n C_p (0)$

$= 0J$

7 0

4 years ago