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Tomtit [17]
3 years ago
6

Brainliest will be given! Please help!

Chemistry
1 answer:
Marat540 [252]3 years ago
7 0
Use this formula to find it
amount \: left = starting \: amount \:  {( \frac{1}{2})}^{ \frac{time \: gone}{half \: life} }
Starting amount = 40g
Half life = 4 days
Time gone = 12 days
Amount left = 40 (1/2)^12/4
= 40 (1/2)^3
= 40 (1/8)
= 5 grams
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What is the area of triangle ABC with vertices A(x¹,y¹), B(x²,y²)and C (x³,y³)??????????<br>​
AlexFokin [52]

Answer:

Area = \frac{1}{2}|x_1(y_2 - y_3)+x_2(y_3 - y_1)+x_3(y_1 - y_2)|

Area = 2\ units^2

Explanation:

Given

A = (x_1,y_1)

B = (x_2,y_2)

C = (x_3,y_3)

Required

Determine the area

The area of a triangle is :

Area = \frac{1}{2}|A_x(B_y - C_y) + B_x(C_y - A_y) + C_x(A_y - B_y)|

By substituting values for the x and y coordinates of A, B and C;

We have:

Area = \frac{1}{2}|x_1(y_2 - y_3)+x_2(y_3 - y_1)+x_3(y_1 - y_2)|

So:

For instance

A = (0,3)

B= (2,1)

C = (2,3)

The area is:

Area = \frac{1}{2}|0(1-3) + 2(3-3) + 2(3-1)|

Area = \frac{1}{2}| 2*0 + 2*2|

Area = \frac{1}{2}| 0 + 4|

Area = \frac{1}{2}|4|

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7 0
3 years ago
3. What are the products of a neutralization reaction?
Nadusha1986 [10]

Answer:

Neutralization reactions occur when two reactants, an acid and a base, combine to form the products salt and water.

5 0
3 years ago
Read 2 more answers
Which process results in a chemical change?
Alla [95]
D) burning magnesium ribbon, as combustion is a chemical reaction so causes chemical change. The other 3 options do not involve reactions so there isn't a chemical change.
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3 years ago
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The temperature of a 100.0 g sample of water is raised from 30degrees celsius to 100.0 degrees celsius. How much energy is requi
worty [1.4K]

Answer:

29260J

Explanation:

Given parameters:

Mass of water sample  = 100g

Initial temperature = 30°C

Final temperature  = 100°C

Unknown:

Energy required for the temperature change = ?

Solution:

The amount of heat required for this temperature change can be derived from the expression below;

     H  = m c (ΔT)

H is the amount of heat energy

m is the mass

c is the specific heat capacity of water  = 4.18J/g°C

ΔT is the change in temperature

Now insert the parameters and solve;

          H  = 100 x 4.18 x (100 - 30)

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6 0
2 years ago
Describe an experiment to show that water contains hydrogen and oxygen only​
kondaur [170]

Answer:

Electrolysis

Explanation:

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In the electrolysis of water, electricity is passed through acidified water to cause it to decompose.

The electrolysis of water is also known as the electrolysis of dilute tetraoxosulphate  (VI) acid.

At the cathode, H⁺ ions are discharged and hydrogen gas is liberated:

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At the anode, both the sulfate ion and hydroxyl ions migrate to this electrode. Only the OH⁻ is selected for preferential discharge due to its lower position in that activity series.

         4OH⁻  →   2H₂O    +    O₂     +     4e⁻

Oxygen gas is produced at the anode.

This electrolysis demonstrates the volumetric composition of water that is, 2 volumes of hydrogen at the cathode and 1 volume of oxygen at the anode.

5 0
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