HELP FAST! PLEASE
This is due in 4 hrs!!!!! Ahhhh

Answer:

I want to say 10 grams

Explanation:

80 grams is your start

and a half-life is half of that so...

half of 80 ( and or 80/2)

40 grams

then another half is...

half of 40 (and or 40/2)

20 grams

then another half-life is...

half of 20 (and or 20/2)

10 grams

That is 3 half-life of 80 grams

*becareful not to just divide 80 / 3 you will get 26.666 (repeating) that is  incorrect

you want a half of a half of a half

Answer:

Explanation:

The kinetic energy of an object can be found by using the formula

[tex]k = \frac{1}{2} m {v}^{2} \\ [/tex]

m is the mass

v is the velocity

From the question we have

[tex]k = \frac{1}{2} \times 3 \times {2}^{2} \\ = \frac{1}{2} \times 3 \times 4 \\ = 3 \times 2[/tex]

We have the final answer as

Hope this helps you

The car's velocity after 5s : 10 m/s

Given

velocity=v=72 km/h=20 m/s

time=t = 5 s

acceleration=a = -2 m/s²

Required

velocity after 5s

Solution

Straight motion changes with constant acceleration

[tex]\tt v_f=v_i+at[/tex]

vf=final velocity

vi = initial velocity

Input the value :

[tex]\tt v_f=20+(-2).5\\\\v_f=20-10\\\\v_f=10~m/s[/tex]

The car is decelerating (acceleration is negative) so that its speed decreases

Answer:

The Velocity after 5s if its acceleration is -2m/s is 10 m / s.

Explanation:

The motion equation is given by v = u + a x t.

Initial speed (u) is equal to 72 km/h.

Acceleration (a) equals 2 m/s2.

Time (t) = 5s.

Changing the initial velocity's direction from km/h to m/s:

1 km/hr is equal to 1000 m/3600 s/5/18 m/s.

velocity (u) is equal to 72 x (5 / 18) m/s, or 20 m/s.

The motion equation can be used to calculate final velocity.

To change values in the equation of motion, do the following:

Final Velocity (v) = u + a x t

v = u + a x t

v = 20 m/s + (-2 x 5) m/s

v = (20 - 10)m/s v = 10 m/s

As a result, the car's speed after 5 seconds will be 10 m/s.

To know more about Velocity,

brainly.com/question/24567267

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Answer:

A

Explanation:

hope it helps

Answer:

A

Explanation:

I got right

Answer:

well for me I think

Explanation:

immigration is the movement which involves an individual moving from a present place to another environment

That is going out

WHILE

Emigration is the process where a person comes into a particular environment

That means coming in

Answer:

I think that the answers A, not 100% sure tho

Explanation:

Because the problem says "highly radioactive" chemicals and gamma rays are highly radioactive chemicals, and gamma rays are very penetrating to the human body

N - 7 - 1s2 2s2 2p3

O - 16 - 1s2 2s2 2p6 3s2 3p4

Mn - 25 - 1s2 2s2 2p6 3s2 3p6 4s2 3d5

Ga - 31 - 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p1

Answer:

a. volcanic changes create new land

The ratio of concentration of ammonia and ammonium chloride : 0.05

Given

pOH=5

Kb for NH3 =1.8 x 10-4

Required

The ratio of concentration of ammonia (NH₃) and ammonium chloride(NH₄Cl)

Solution

Solutions containing ammonia and its salt: ammonium chloride are called alkaline buffers

Can be formulated : ( for the same of the volume, mol=concentration)

[tex]\tt \displaystyle [OH-]=Kb\times\frac{weak\:base\:mole}{salt\:mole\times valence}[/tex]

pOH=-log [OH⁻]

pOH=5⇒[OH⁻]=10⁻⁵

Valence for NH₄Cl = 1, so the concentration ratio :

[tex]\tt 10^{-5}=1.8\times 10^{-4}\times \dfrac{[~NH_3]}{[NH_4Cl]}\\\\0.05=\dfrac{[~NH_3]}{[NH_4Cl]}[/tex]

Answer:

Zinc reacts with dilute sulphuric acid to produce hydrogen gas (H2) and zinc sulphate. This is an example of displacement reaction of a non-metal by a metal. ... ZnSO4 is different in chemical composition and chemical properties than Zn and H2SO4 so it is a chemical change.

Answer:

Reaction of Zinc with Dilute Sulphuric Acid

Zinc is more reactive than hydrogen and it displaces hydrogen from dilute acids. Zinc reacts with dilute sulphuric acid to form zinc sulphate and hydrogen gas is evolved. This is a single displacement reaction of a non-metal by a metal. ... So, this reaction is a chemical change.

Answer:

The phosphorus ylide reacts with the aldehyde or ketone to make an oxaphosphetane.

Explanation:

The Wittig reaction is a reaction that occurs between a phosphorus ylide and an aldehyde or ketone. The final products are an alkene and triphenyl phosphine oxide.

The first step in the reaction is the attack of the phosphorus ylide on the aldehyde or ketone. This is followed by attack of oxygen on phosphorus to form a [2+2] cycloaddition product (oxaphosphetane)  which  decomposes to form the alkene and triphenylphosphine oxide.

Answer:

MgSO_3(s) + 2 HNO_3(aq) rightarrow Mg^2+(aq) + 2 NO_3^-(aq) + SO_2(g) + H_2O(l) b.

Explanation:

The balanced net ionic equation for the reaction of magnesium sulfite with nitric acid is a. MgSO_3(s) + 2 HNO_3(aq) rightarrow Mg^2+(aq) + 2 NO_3^-(aq) + SO_2(g) + H_2O(l) b.

Answer:

1. 0.28M

2. 24mL

3. 0.002295moles of NaOH.

Explanation:

1. The 6.0M HCl solution is diluted from 35mL to 750mL, that is:

750mL / 35mL = 21.43 times

The 6.0M HCl solution is diluted 21.43 times, the final concentration is:

6.0M / 21.43 = 0.28M

2. First, we need to convert grams of CuNO3 to moles and then, as molarity is moles per liter we can solve for volume of solution in liters and convert it to mililiters:

Moles CuNO3 -Molar mass 124.9g/mol:

2.49g * (1mol / 124.9g) = 0.020 moles of CuNO3

Volume is:

0.020 moles * (1L / 0.830mol) = 0.0240L * (1000mL / 1L) = 24mL

3. In 13.5mL = 0.0135L of 0.17M NaOH the moles are:

0.0135L * (0.17mol / L) = 0.002295moles of NaOH

Answer:

–0.360 M/s

Explanation:

Answer:

Three atoms of magnesium can have different masses because each of the three atoms has a different number of neurons.

I hope this helped :)

The differences in masses of the three magnesium atom is due to there differences in there neutron number

Isotopes are members of an element that all have the same number of protons but different numbers of neutrons.

These are 2 or mores type of atoms that have the same atomic number but different nucleon numbers due to the different number of neutron in the nuclei.

The reason why three atoms of magnesium has different masses is due to Isotropy.

The differences in masses of the three magnesium atom is due to there differences in there neutron number.

The differences in masses is caused by the differences of their neutron number.

learn more about isotopy here: https://brainly.com/question/25305592?referrer=searchResults

Answer:

Kc < 1

Explanation:

Since the product formed is in solid state, from law of mass action.

Kc = 0

[Ba2+]³[PO4³-]²

hence Kc is 0

Moles of NO formed : 0.833

Given

2.5 moles of NO2

Required

moles of NO formed

Solution

Reaction

3 NO₂(g) + H₂O(l) = 2 HNO₃(aq) + NO(g)

The reaction coefficient in a chemical equation shows the mole ratio of the compounds in the reactants and products

From the equation, mol ratio of NO₂ and NO = 3 : 1, so moles of NO :

[tex]\tt moles~NO=\dfrac{1}{3}\times 2.5\\\\moles~NO=0.833[/tex]

Answer:

an electromagnetic wave

Explanation:

Answer: is that a question or

Explanation:

Answer:

its c

Explanation:

Answer:

B. 20, 22, 20

Explanation:

The atomic number (Z) of calcium is 20, that is, it has 20 protons.

The mass number (A) of calcium-42 is 42. The mass number is equal to the sum of protons and neutrons. Then,

p⁺ + n⁰ = 42

n⁰ = 42 - p⁺

n⁰ = 42 - 20

n⁰ = 22

Since calcium is electrically neutral, it has the same number of protons (+) and electrons (-). Then, calcium has 20 electrons.

Answer:

Energy cannot be destroyed or created.

C. i know this is right

Explanation:

Answer:

I think B. O2+

Explanation:

Answer:

B

it must be O2- not O2+, because it's an anion not a cation.

Hey there!:

Molar mass N₂ = 28.0134 g/mol

28.0134 g ------------------- 22.4 L (at STP )

mass  N₂ -------------------- 50.0 L

mass N₂ = 50.0 x 28.0134 / 22.4

mass N₂ = 1400.67 / 22.4

mass N₂ = 62.529 g

Hope this helps!

Time to slide down : 2.4 s

Given

total length of slide = 12 m

Randy's speed = 5 m/s

Required

time to slide down

Solution

Randy's motion can be said to be a straight, regular motion at a constant speed

Can be formulated

d = v x t

d = distance, m

v = velocity, m / s

t = time, s

we plug in the known values in the formula

[tex]\tt t=\dfrac{d}{v}\\\\t=\dfrac{12~m}{5~m/s}\\\\t=2.4~s[/tex]