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3 years ago

How many moles of sodium are present in 17 g of Na?

Chemistry

1 answer:

11Alexandr11 [23.1K]3 years ago

8 0

Answer:

1. 0.74mol

2. 0.42mol

3. 2.125mol

4. 0.301mol

5. 4.52 × 10^23 particles

Explanation:

Number of moles (n) in a substance can be found using the formula:

mole (n) = mass/molar mass

Using this formula, the following moles are calculated:

1. Molar of Na = 23g/mol

mole = 17/23

mole = 0.74mol

2. Molar mass of Na2SO4 = 23(2) + 32 + 16(4)

= 46 + 32 + 64

= 142g/mol

Mole = 60/142

mole = 0.42mol

3. Molar mass of CO2 = 12 + 16(2)

= 12 + 32

= 44g/mol

mole = 93.5/44

mole = 2.125mol

4. Molar mass of sodium nitrate (NaNO3) = 23 + 14 + 16(3)

= 23 + 14 + 48

= 85g/mol

mole = 25.6/85

mole = 0.301mol

5. Number of particles in one mole of a substance is 6.022 × 10^23 particles. Hence, in 0.75mol of calcium hydroxide (Ca(OH)2, there will be;

0.75mol × 6.02 × 10^23

= 4.515 × 10^23

= 4.52 × 10^23 particles

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Answer:

$\Delta \rho =2.22 g/mL$

Explanation:

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In this case, since a change in science is widely known to be considered as a subtraction between the the final and initial values of two measured variables and is represented via Δ, here the final density is 5.43 g/mL and the initial one was 3.21 g/mL, therefore, the change in density is:

$\Delta \rho=\rho _f-\rho _i\\ \\\Delta \rho=5.43g/mL-3.21g/mL\\\\\Delta \rho =2.22 g/mL$

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3 years ago

What is the difference between a distraction and a reaction

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The difference between a distraction and a reaction is.... A distraction is a thing that prevents someone from giving full attention to something else. A reaction is a action performed or a feeling experienced in response to a situation or an event.

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Jasper made a list of the properties of electromagnetic waves. Identify the mistake in the list.

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Answer:

B. Line 2 has a mistake

Explanation:

1. All electromagnetic waves are made of both electric and magnetic fields (hence the name electromagnetic).

2. All electromagnetic waves are transverse, and not longitudinal.

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3 years ago

Student have a receipt which calls for 1.15 lb of flour, but, of course, in France you will need to purchase flour in kilograms.

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0.52164 kg of Flour

<u>Explanation:</u>

We have to convert lb (pounds) kg (kilograms), by using the conversion unit,

1 lb = 0.4536 kg

So to convert 1.15 lb into kg, we have to multiply 1.15 by 0.4536.

$1.15 \times 0.4536$ = 0.52164 kg of Flour

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4 years ago

Object A specific heat is 2.45 J/g C and object B specific heat is 0.82 J/g C. Which object will heat up more if they have the s

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Answer: Object B will heat up more.

Explanation:

The formula for specific heat is as follows.

Q = $m C \Delta T$

Where,

Q = heat provided

m = mass

C = specific heat

$\Delta T$ = change in temperature

Now, both the objects have same mass and equal amount of heat is applied.

According to the formula, the equation will be as follows.

$Q_{1}$ = $Q_{2}$

$m C_{1}\Delta T$ = $m C_{2}\Delta T_{2}$

Cancel m from both sides, as mass is same. Therefore,

$C_{1} (T_{f} - T_{i})_A$ = $C_{2}(T_{f} - T_{i})_B$

Cancel out the initial temperature and put the values of specific heat, then the equation will be as follows.

$2.45 (T_{f})_A$ = $0.82(T_{f})_B$

Therefore, from the above equation it can be concluded that the object with low specific heat will heat up more as its specific heat will be inversely proportional to its final temperature.

Hence, object B will heat up more.

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3 years ago