What doe the elements in these groups have in common? a)alkali metals b) halogens c) noble gases

For Questions 1 through 4 - Consider a solution prepared by combining 45.0 g of BaCl2 with enough water to prepare a 750.0 mL of

astra-53 [7]

Answer: The molality of barium chloride solution is 0.289 m

Explanation:

To calculate the mass of water, we use the equation:

$\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}$

Density of water = 1 g/mL

Volume of water = 748 mL

Putting values in above equation, we get:

$1g/mL=\frac{\text{Mass of water}}{748mL}\\\\\text{Mass of water}=(1g/mL\times 748mL)=748g$

To calculate the molality of solution, we use the equation:

$\text{Molality}=\frac{m_{solute}\times 1000}{M_{solute}\times W_{solvent}\text{ (in grams)}}$

where,

$m_{solute}$ = Given mass of solute (barium chloride) = 45.0 g

$M_{solute}$ = Molar mass of solute (barium chloride) = 208.23 g/mol

$W_{solvent}$ = Mass of solvent (water) = 748 g

Putting values in above equation, we get:

$\text{Molality of barium chloride solution}=\frac{45\times 1000}{208.23\times 748}\\\\\text{Molality of barium chloride solution}=0.289m$

Hence, the molality of barium chloride solution is 0.289 m

5 0

3 years ago

P O R F A V O R

ale4655 [162]

Answer:

a. 45×10³ kg

b. 1.25 kg

c. 5443200 s

d. 2.69×10⁻⁴ m/s²

e. 2.57×10⁻⁶N

f. 7.48×10⁻³ m /s²

g. 2.45 Pa

h. 10 m/s

Explanation:

The SI units are: kg, m, s, N, K, A, Pa, J and cd

a. 1 g is the mass for 1 cm³. We convert the m³ to cm³

45 m³. 1×10⁶ cm³ / 1 m³ = 45×10⁶ cm³

By the way, 45×10⁶ cm³ = 45×10⁶ g

We convert the g to kg → 45×10⁶ g . 1 kg / 1000 g = 45×10³ kg

b. As 1 g = 1 cm³, we convert the cm³ to g and then, the g to kg

1250 cm³ = 1250 g → 1250 g . 1kg / 1000 g = 1.25 kg

c. 1 day has 24 hours; 1 hour has 60 minutes; 1 minute has 60 seconds

1 hour has 3600 s. Then 24 h . 3600 s / 1 h = 86400 s

86400 s/d. 63 d = 5443200 s

d. 1 min² = 3600 s²

97 cm / 3600 s² = 0.0269 cm/s² / 100 = 2.69×10⁻⁴ m/s²

e. 927 g.cm / min² / 3600 s² = 0.2575 g.cm/s² → dyn

We need to convert dyn to N

1 dyn = 10⁻⁵N → 0.2575 dyn . 10⁻⁵N / 1dyn = 2.57×10⁻⁶N

f. 1 m/s² = 12960 km/h²

12960 km/h² . 1 m/s² / 97 km/h² = 7.48×10⁻³ m /s²

g. 2500 g/cm² . 1kg / 1000 g = 2.5 kg/cm²

1 Pa = 1.02kg/cm²

2.5 kg/cm² . 1 Pa / 1.02 kg/cm² = 2.45 Pa

h. 1 h = 3600 s

36 km / 3600 s = 0.01 km /s → 0.01 km . 1000 m / 1 km = 10

= 10 m/s

5 0

3 years ago

What does botanist study? A. Boats B.Matter C. chemicals D. Plants

4vir4ik [10]

What does botanist study?

$\implies {\blue {\boxed {\boxed {\purple {\sf {D.\: Plants}}}}}}$

$\bold{ \green{ \star{ \orange{Hope\:it\:helps.}}}}⋆$

8 0

4 years ago

What it the oxidation number for cl? A. -2 B. +2 C. -1 D. +1

brilliants [131]

Answer:

c.

Explanation:

it is c.-1 because oxidation number of cl is-1

5 0

3 years ago

In a typical mass spectrum, a smaller signal is observed at a mass 1 amu higher than the molecular ion peak. Why

Nina [5.8K]

Answer:

Answer is explained below in the explanation section

Explanation:

Smaller signal is observed at a mass 1 amu because small percentage of the compound will have carbon isotope of 13C instead of 12C.

As we know, mass spectrometry is done as a small compound is first vaporized and then bombarded to ionize it. And then, those ions are accelerated forward and then at some point ions are separated and deflected by the application of magnetic field.

And finally hits the detector to give us a spectrum to read. So, in this whole procedure, there can be a small percentage of carbon isotope of 13C instead of 12C in that compound and showed in the spectrum as a smaller signal at a mass 1 amu.

8 0

3 years ago