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2 years ago

Please help me school ends tomorrow

Chemistry

1 answer:

wolverine [178]2 years ago

3 0

Answer:

<h2>D) clapping hands </h2>

Explanation:

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2 grams of a substance was dissolved in 75.0 g of water resulting in a temperature decrease from 23.1 ⁰C to 18.7 ⁰C. The specifi

RUDIKE [14]

<h3>Answer:</h3>

1379.4 Joules

<h3>Explanation:</h3>

The quantity of heat is calculated multiplying the mass of a substance by heat capacity and the change in temperature.

Therefore;

Quantity of heat = Mass × specific heat capacity × Change in temperature

Q = mcΔT

In this case;

The substance dissolved in water gained heat while water lost heat energy.

Thus, Heat gained by the substance = heat lost by water

Heat associated with the water

Mass of water = 75 g

Change in temperature = 4.4°C

Specific heat capacity = 4.18 J/g·⁰C

Heat = mcΔT

= 75 g × 4.18 J/g·⁰C × 4.4 °C

=1379.4 Joules

5 0

2 years ago

A sample of gold has a mass of 100 grams and a volume of 5cm^3, calculate the density by dividing the mass by volume

Dafna11 [192]

Answer:

20cm^2

Explanation:

Here, Density= Mass/ Volume

=100/5

= 20 cm^2

7 0

2 years ago

Describe polar covalent bonds using water as an example

Dahasolnce [82]

<span>A covalent bond is a bond formed by atom sharing.
In water molecule, there are twice the number of hydrogen atoms than the oxygen atoms. Its structure is H-O-H. The electronegative difference between the H and O allows them to be polar because on side there is positive charge and on another side there is negative charge.</span>

3 0

2 years ago

Balance the following redox equation in acidic solution using the smallest integers possible and select the correct coefficient

romanna [79]

Answer:

Coefficient of $H^{+}(aq)$ is more than 4

Explanation:

Oxidation: $Sn^{2+}(aq)\rightarrow Sn^{4+}(aq)$

Balance charge: $Sn^{2+}(aq)-2e^{-}\rightarrow Sn^{4+}(aq)$ ......(1)

Reduction: $Cr_{2}O_{7}^{2-}(aq)\rightarrow Cr^{3+}(aq)$

Balance Cr: $Cr_{2}O_{7}^{2-}(aq)\rightarrow 2Cr^{3+}(aq)$
Balance O and H in acidic medium: $Cr_{2}O_{7}^{2-}(aq)+14H^{+}(aq)\rightarrow 2Cr^{3+}(aq)+7H_{2}O(l)$
Balance charge: $Cr_{2}O_{7}^{2-}(aq)+14H^{+}(aq)+6e^{-}\rightarrow 2Cr^{3+}(aq)+7H_{2}O(l)$ .......(2)

$[3\times Equation-(1)]+Equation(2)$ gives balanced equation:

$3Sn^{2+}(aq)+Cr_{2}O_{7}^{2-}(aq)+14H^{+}(aq)\rightarrow 3Sn^{4+}(aq)+2Cr^{3+}(aq)+7H_{2}O(l)$

So coefficient of $H^{+}(aq)$ is more than 4

3 0

2 years ago

A bottle of the antiseptic hydrogen peroxide is labeled 3.0% (v/v). How many mL of hydrogen peroxide are in a 400 mL bottle of t

zepelin [54]

There are several ways of expressing concentration of solution. Few of them are listed below
1) mass percentage
2) volume percentage
3) Molarity
4) Normality
5) Molality

In most of the drugs, concentration is expressed either in terms of mass percentage or volume percentage. For, solid in liquid type systems, mass percentage is convenient way of expressing concentration, while for liquid in liquid type solutions, expressing concentration in terms of volume percentage is preferred. Present system is an example of liquid in liquid type solution

Here, concentration of H2O2 is given antiseptic = 3.0 % v/v

It implies that, 3ml H2O2 is present in 100 ml of solution

Thus, 400 ml of solution would contain 4 X 3 = 12 ml H2O2

3 0

3 years ago