Can someone help me on this letter E please

Answer:

116 years

Explanation:

To solve this, we will use the half life equation;

A(t) = A_o(½)^(t/t_½)

Where;

A(t) is the amount of strontium left after t years;

A_o is the initial quantity of strontium that will undergo decay;

t_½ is the half-life of strontium

t is the time it will take to decay

We are given;

A(t) = 7.5 g

A_o = 120 g

From online values, half life of strontium-90 is 29 years. Thus, t_½ = 29

Thus;

7.5 = 120 × ½^(t/29)

Divide both sides by 120 to get;

7.5/120 = ½^(t/29)

0.0625 = ½^(t/29)

In 0.0625 = (t/29) In ½

-2.772589 = (t/29) × (-0.693147)

(t/29) = -2.772589/(-0.693147)

t/29 = 4

t = 29 × 4

t = 116 years

Answer:

Because we are not perfect

Explanation:

This day is added to the calendar as a corrective measure, because the Earth does not orbit the sun in precisely 365 days.

An earthworm has a closed circulatory system.

The earthworm has a closed circulatory system. An earthworm circulates blood exclusively through vessels. There are three main vessels that supply the blood to organs within the earthworm.

As important as they are alive for distributing nutrients and organisms and decomposing matter, worms are also very important in the food chain. They provide a crucial protein-rich source of food for other important species like birds, hedgehogs and frogs.

They may live up to eight years, though one to two is more likely. Full size for an earthworm varies among species, ranging from less than half an inch long to nearly 10 feet.

Learn more about earthworm here:- https://brainly.com/question/13938105

#SPJ1

Answer:

NaCl (Na is a metal and Cl is a nonmetal) MgO (Mg is a metal and O is a nonmetal) Al2O3, NaF, Na2O

Explanation:

You have to have a metal and a non metal together for it to be ionic

Answer: D

Explanation:

Answer:

0.807 moles

Explanation:

No of molecules = No of mole × Avogadro's number

No of mole = No of molecules / Avogadro's number

No of mole = 5.24×10^23/6.02×10^23

0.870 moles

Answer:

I NEED TO KNOW THIS TOO

Explanation:

IVE BEEN LOOKING FOR THE ANSWER

Answer:

Li

Explanation:

Answer:

Summary. To summarize, the periodic table is important because it is organized to provide a great deal of information about elements and how they relate to one another in one easy-to-use reference. The table can be used to predict the properties of elements, even those that have not yet been discovered.

Explanation:

by rounding them to the neerest 10

Answer:

rest until and unless an external force is applied.

Answer:

ZnO + H2SO4 = ZnSO4 + H2O | Chemical reaction and equation

Explanation:

gloogle

Answer:

C. Daily Organizer. Also called an agenda. We usually write notes in them for school related things so the answer is pretty self explanatory.

Elements which composed of an equal amount of three components protons, neutrons and electrons are considered neutral elements. example of neutral elements are hydrogen, helium, lithium and beryllium...

Answer:

5446.8 J

Explanation:

From the question given above, the following data were obtained:

Mass (M) = 50 g

Initial temperature (T₁) = 70 °C

Final temperature (T₂) = 192.4 °C

Specific heat capacity (C) = 0.89 J/gºC

Heat (Q) required =?

Next, we shall determine the change in the temperature. This can be obtained as follow:

Initial temperature (T₁) = 70 °C

Final temperature (T₂) = 192.4 °C

Change in temperature (ΔT) =?

ΔT = T₂ – T₁

ΔT = 192.4 – 70

ΔT = 122.4 °C

Finally, we shall determine the heat required to heat up the block of aluminum as follow:

Mass (M) = 50 g

Specific heat capacity (C) = 0.89 J/gºC

Change in temperature (ΔT) = 122.4 °C

Heat (Q) required =?

Q = MCΔT

Q = 50 × 0.89 × 122.4

Q = 5446.8 J

Thus, the heat required to heat up the block of aluminum is 5446.8 J

Answer:

Beautiftul, begging under F

honest, beginning in thrid line under A

hopeful, fifth line under F

Explanation:

Answer:

ocean

Explanation:

because its easy

Answer:

the answer maybe is 61.5 years (please check with others) tq

Explanation:

40/2=20

20/2=10

10/2=5

5/2=2.5

2.5/2=1.25

so one half life is 12.3 years

then 12.3 ×5 =61 .5

(why 5 ? because it decay 5 times to get 1.25 from 20)

Answer: energy is transferred, but it can go to the products or the reactants.

Explanation: in a chemical reaction, the atoms and molecules that interact with each other are called reactants.

The proton is a postitive charge, therefore, being 1 (proton) matched to positive. Whilst neutron (2) is matched to neutral. Thus electron (3) is matched to negative.

Answer:

when you burn wood in a campfire, chemical energy is converted to heat and light energy.

Explanation :

When wood is burned stored potential energy ( in the form of chemical energy ) in the log is released due to heating by other excited atoms . This process is called combustion and requires presence of oxygen. So,  combustion can be defined as a process which changes chemical energy into kinetic energy in the form of heat.  In case of combustion  an organic say wood in this case combines with oxygen present in the atmosphere to give off carbon dioxide, water and energy in the form of heat and light .    

Answer:

A. During the summer, Earth's rotational axis is parallel to the Sun's rotational axis.

Explanation:

Actually, though, the Earth is tilted 23.4 degrees! (A circle is 360 degrees.) This tilt is the reason that days are longer in the summer and shorter in the winter. The hemisphere that's tilted closest to the Sun has the longest, brightest days because it gets more direct light from the Sun's rays.

Plz mark me brainliest if correct :)

During summer days, north pole of earth is exposed to sun because ofthe tilt of earth's rotational axis. Thus, The region of Earth experiencing summer is tilted toward the Sun while the region experiencing winter is tilted away from the Sun.

Summer is a season in earth. There are different seasons in earth namely, summer, winter, spring, autumn etc. These season are arising due the revolution of earth around sun.

The distance of different regions of earth from sun changes due to the revolution of earth. Thus heat gained by these regions will be different in different seasons.

The north pole in summer gains more heat and light energy because of tilt in the axis of earth is towards the sun. Hence, the day time will be longer in summer than the winter. In winter, the earth is relatively apart from sun and thus  tilt is and gains less light and heat  .

To find more on seasons, refer here:

https://brainly.com/question/19009677

#SPJ6

Answer:

Stronger

And its science

Explanation:

Answer:

stronger for top.

weaker for bottom.

passed all sciences in freshman year :D

Answer:

It Is Transitional Energy.

Explanation: I Took The Quiz And Got It Wrong. It Showed That Transitional Energy Was The Correct Answer.

Answer:

heat energy

Explanation:

Answer:

I helped take care of my baby cousin :)

Explanation:

Answer:

Oh thats great..

But I hate juice :(

Which statement about photosynthesis is FALSE?

Answer:

b. Oxygen is needed as a reactant to produce

glucose is the incorrect statement here

Explanation:

plants uses simple raw materials to prepare their food , which includes water ( H2O ) and Carbon dioxide ( CO2 ).

and traps sunlight by Green pigments known as chlorophyll and stores these energy in bonds of glucose molecules

so ,

after this reaction glucose and oxygen is formed as products

● hence we conclude that Oxygen is not needed as a reactant to produce glucose , oxygen is the bi product formed during photosynthesis.