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3 years ago

NEED HELP! thank you!

Chemistry

1 answer:

Zanzabum3 years ago

7 0

Answer:

This is a physical change.

Explanation:

As long as the identity of the substance has not changed, and the element is present before and after, it is a physical change! (Ex: ice melting)

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A battery can provide a current of 4.60 A at 3.40 V for 2.50 hr. How much energy (in kJ) is produced? 1st attempt kJ Energy

Lunna [17]

Answer:

The energy produced equals 140.760 kJ

Explanation:

The relation between power, current and voltage is

$Power=Current\times Voltage$

Applying the given values in the relation above we get

$Power=4.60\times 3.40=15.64W$

Now Since $Power=\frac{Energy}{Time}\\\\Energy=Power\times Time$

Again applying the calculated values we get

$Energy=15.64\times 2.50\times 3600=140760Joules=140.76kJ$

4 0

3 years ago

Calculate the number of atoms in 5 moles H₂O.

oksano4ka [1.4K]

Answer:

90.35 × 10²³ atoms

Solution:

1 molecules of H20 contains 3 atoms,.

And we know that one mole of any molecule contains 6.023 × 10²³ atoms from Avogadro's number,

hence 5 moles of H20 will contain = 5× 6.023 × 10²³ × 3 atoms = 90.35 × 10²³ atoms!

<em><u>Thanks for joining brainly community!</u></em>

4 0

2 years ago

Calculate the amount of energy , in Joules, required to raise the temperature of 15.5 g of liquid water from 0.00o C to 75.0 oC.

deff fn [24]

Answer:

10043.225 J

Explanation:

We'll begin by calculating the amount of heat needed to change ice to water since water at 0°C is ice. This is illustrated below:

Mass (m) = 15.5g

Latent heat of fussion of water (L) = 334J/g

Heat (Q1) =..?

Q1 = mL

Q1 = 15.5 x 334

Q1 = 5177 J

Next, we shall calculate the amount of heat needed to raise the temperature of water from 0°C to 75°C.

This is illustrated below:

Mass = 15.5g

Initial temperature (T1) = 0°C

Final temperature (T2) = 75°C

Change in temperature (ΔT) = T2 – T1 = 75 – 0 = 75°C

Specific heat capacity (C) of water = 4.186J/g°C

Heat (Q2) =?

Q2 = MCΔT

Q2 = 15.5 x 4.186 x 75

Q2 = 4866.225 J

The overall heat energy needed is given by:

QT = Q1 + Q2

QT = 5177 + 4866.225

QT = 10043.225 J

Therefore, the amount of energy required is 10043.225 J

8 0

3 years ago

Can you pls tell me the word equations for all these equations

Leokris [45]

Answer:

Below

Explanation:

Balanced form;

$2C_6H_6 +15O_2 -> 12CO_2+6H_2O\\\\ Ca_3(PO_4)_2 +8C -> Ca_3P_2 +8CO\\\\2HNO_2+O_2 -> 2HNO_3\\\\Ca(OH)_2 + CO_2 -> CaC0_3+H_2O\\\\2K +Br_2 ->2KBr\\\\2NaOH+FeSO_4 -. Na_2SO_4 +Fe(OH)_2$

1.Benzene + Dioxygen = Carbon Dioxide + Water

2.Tricalcium phosphate +Carbon = Calcium phosphide + carbon monoxide

3.Nitrous acid react with oxygen to produce nitric acid.

4.This means that the carbon dioxide and limewater react to produce calcium carbonate and water.

5.Potassium react with bromine to produce potassium bromide

6. An aqueous solution of ferrous sulphate reacts with aqueous solution of sodium hydroxide to form a precipitate of ferrous hydroxide and sodium sulphate remains in the solution.

5 0

3 years ago

the formula of calcium oxide is CaO. What is the formula of the ionic compound containing calium abd sulfate ions

sineoko [7]

Answer:

$CaS$

Explanation:

Hello!

In this case, since calcium's oxidation state when forming ionic bonds is +2 and sulfur's oxidation state when bonding those bonds is -2, for the required formula we write:

$Ca^{2+}S^{2-}$

Now, since they have the same charge number, we infer the ionic compound formed when they bond is calcium sulfide:

$CaS$

Best regards!

5 0

2 years ago