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2 years ago

G8_SCIENCE_BSA_21_22

Chemistry

1 answer:

S_A_V [24]2 years ago

8 0

Answer:

Explanation: Over the course of a year, areas near Earth’s equator receive more direct energy from the Sun than areas near Earth’s poles. Which of the following correctly describes one result of this heating pattern?

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Which piece of the planetary object data could be used to decide if there actually is a solid surface to land on?

zloy xaker [14]

A planetary surface is where the solid (or liquid) material of the outer crust on certain types of astronomical objects contacts the atmosphere or outer space. Planetary surfaces are found on solid objects of planetary mass, including terrestrial planets (including Earth), dwarf planets, natural satellites, planetesimals and many other small Solar System bodies (SSSBs).[1][2][3] The study of planetary surfaces is a field of planetary geology known as surface geology, but also a focus of a number of fields including planetary cartography, topography, geomorphology, atmospheric sciences, and astronomy. Land (or ground) is the term given to non-liquid planetary surfaces. The term landing is used to describe the collision of an object with a planetary surface and is usually at a velocity in which the object can remain intact and remain attached.

In differentiated bodies, the surface is where the crust meets the planetary boundary layer. Anything below this is regarded as being sub-surface or sub-marine. Most bodies more massive than super-Earths, including stars and gas giants, as well as smaller gas dwarfs, transition contiguously between phases, including gas, liquid, and solid. As such, they are generally regarded as lacking surfaces.

Planetary surfaces and surface life are of particular interest to humans as it is the primary habitat of the species, which has evolved to move over land and breathe air. Human space exploration and space colonization therefore focuses heavily on them. Humans have only directly explored the surface of Earth and the Moon. The vast distances and complexities of space makes direct exploration of even near-Earth objects dangerous and expensive. As such, all other exploration has been indirect via space probes.

Indirect observations by flyby or orbit currently provide insufficient information to confirm the composition and properties of planetary surfaces. Much of what is known is from the use of techniques such as astronomical spectroscopy and sample return. Lander spacecraft have explored the surfaces of planets Mars and Venus. Mars is the only other planet to have had its surface explored by a mobile surface probe (rover). Titan is the only non-planetary object of planetary mass to have been explored by lander. Landers have explored several smaller bodies including 433 Eros (2001), 25143 Itokawa (2005), Tempel 1 (2005), 67P/Churyumov–Gerasimenko (2014), 162173 Ryugu (2018) and 101955 Bennu (2020). Surface samples have been collected from the Moon (returned 1969), 25143 Itokawa (returned 2010), 162173 Ryugu and 101955 Bennu.

3 0

2 years ago

The concentration of a biomolecule inside a rod‑shaped prokaryotic cell is 0.0035 M . Calculate the number of molecules inside t

timama [110]

Answer: This rod-shape prokaryotic cell has 3.740,734725‬ molecules

Explanation:

Step 1 : given data

Molarity of the prokaryotic cell = 0.0035 M

Length of the cell = 4.2 μm = 4.2 * 10^-6 m

diameter of the cell = 1.3 μm = 1.3 * 10^-6 m

Step 2: calculate volume

To calculate volume of a rod, weneef to know the radius.

V = r ² × l

The radius = half of the diameter : r = d/2 ⇒ (1.3 * 10^-6 m)/2 = 0.65 * 10^-6 m

V= (0.65 * 10^-6 m)² * 4.2 * 10^-6 m = 1.7745 * 10 ^-18 L

Step 3: Calculating number of moles

Number of moles = Concentration * Volume

moles = 0.0035 M * 1.7745 * 10 ^-18 L = 6.21075 * 10^-21 moles‬

Step 4: calculating number of molecules

1 mole contains 6.023 * 10 ^-23 molecules

6.21075 * 10^-21 moles contain : 6.21075 * 10^-21 * 6.023 * 10 ^-23 molecules = 3.740,734725‬ molecules

This rod-shape prokaryotic cell has 3.740,734725‬ molecules

4 0

3 years ago

True or false sodium is a member of the transition elements

denpristay [2]

false - sodium is not a member of the transition elements, however copper is a member of the transition elements.

3 0

3 years ago

What is a model that is used to predict possible genotypes and phenotype of offspring?

frutty [35]

This is called the pedigree chart.

7 0

2 years ago

When calcium carbonate is added to hydrochloric acid, calcium chloride, carbon dioxide, and water are produced.

sp2606 [1]

Answer:

Mass of CaCl₂ = 20 g

CaCO is presewnt in excess.

Mass of of CaCO₃ remain unreacted = 7.007 g

Explanation:

Given data:

Mass of calcium carbonate = 25 g

Mass of hydrochloric acid = 13.0 g

Mass of calcium chloride produced = ?

Chemical equation:

CaCO₃ + 2HCl → CaCl₂ + H₂O + CO₂

Number of moles of CaCO₃:

Number of moles of CaCO₃ = Mass /molar mass

Number of moles of CaCO₃= 25.0 g / 100.1 g/mol

Number of moles of CaCO₃ = 0.25 mol

Number of moles of HCl:

Number of moles of HCl = Mass /molar mass

Number of moles of HCl = 13.0 g / 36.5 g/mol

Number of moles of HCl = 0.36 mol

Now we will compare the moles of CaCl₂ with HCl and CaCO₃ .

CaCO₃ : CaCl₂

1 : 1

0.25 : 0.25

HCl : CaCl₂

2 : 1

0.36 : 1/2 × 0.36 = 0.18 mol

The number of moles of CaCl₂ produced by HCl are less it will be limiting reactant.

Mass of CaCl₂ = moles × molar mass

Mass of CaCl₂ =0.18 mol × 110.98 g/mol

Mass of CaCl₂ = 20 g

The calcium carbonate is present in excess.

HCl : CaCO₃

2 : 1

0.36 : 1/2 × 0.36 = 0.18 mol

So, 0.18 moles react with 0.36 moles of HCl.

The moles of CaCO₃ remain unreacted = 0.25 -0.18

The moles of CaCO₃ remain unreacted = 0.07 mol

Mass of of CaCO₃ remain unreacted = Moles × molar mass

Mass of of CaCO₃ remain unreacted = 0.07 mol × 100.1 g/mol

Mass of of CaCO₃ remain unreacted = 7.007 g

7 0

3 years ago