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2 years ago

How can i study for a science quiz for monday

Chemistry

1 answer:

Ket [755]2 years ago

8 0

Going to different website and watching different science videos on the unit you are on

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If irons temperature goes from 50c to 75c in a 20g sample, how many joules of heat were used?

Marina CMI [18]

Answer:

Option D. 230 J

Explanation:

We'll begin by calculating the temperature change of the iron. This can be obtained as follow:

Initial temperature (T₁) = 50 °C

Final temperature (T₂) = 75 °C

Change in temperature (ΔT) =?

ΔT = T₂ – T₁

ΔT = 75 – 50

ΔT = 25 °C

Thus, the temperature change of the iron is 25 °C.

Finally, we shall determine the amount of heat energy used. This can be obtained as follow:

Mass (M) = 20 g

Change in temperature (ΔT) = 25 °C

Specific heat capacity (C) = 0.46 J/gºC

Heat (Q) =?

Q = MCΔT

Q = 20 × 0.46 × 25

Q = 230 J

Thus, the amount of heat used was 230 J

3 0

3 years ago

A gas that exerts a pressure of

spayn [35]

Answer:

3.089 L

Explanation:

From the given information, provided that the no of moles and the temperature remains constant;

$P_1$ = 15.6 psi

$V_1$ = ???

$P_2$ = 25.43 psi

$V_2$ = 1.895 L

Using Boyle's law:

$P_1V_1 =P_2V_2 \\ \\ V_1 = \dfrac{P_2V_2}{P_1} \\ \\ V_1 = \dfrac{25.43 \times 1.895}{15.6} \\ \\ \mathbf{ V_1 = 3.089 \ L}$

4 0

2 years ago

Calculate the number of hydrogen atoms present in 40g of urea, (NH2)2CO

tekilochka [14]

Answer: There are $16.14 \times 10^{23}$ atoms of hydrogen are present in 40g of urea, $(NH_{2})_{2}CO$ .

Explanation:

Given: Mass of urea = 40 g

Number of moles is the mass of substance divided by its molar mass.

First, moles of urea (molar mass = 60 g/mol) are calculated as follows.

$Moles = \frac{mass}{molar mass}\\= \frac{40 g}{60 g/mol}\\= 0.67 mol$

According to the mole concept, 1 mole of every substance contains $6.022 \times 10^{23}$ atoms.

So, the number of atoms present in 0.67 moles are as follows.

$0.67 mol \times 6.022 \times 10^{23} atoms/mol\\= 4.035 \times 10^{23} atoms$

In a molecule of urea there are 4 hydrogen atoms. Hence, number of hydrogen atoms present in 40 g of urea is as follows.

$4 \times 4.035 \times 10^{23} atoms\\= 16.14 \times 10^{23} atoms$

Thus, we can conclude that there are $16.14 \times 10^{23}$ atoms of hydrogen are present in 40g of urea, $(NH_{2})_{2}CO$ .

7 0

2 years ago

How many miligrams are in 75 nanogram?

Naddik [55]

Answer:

7.5e-5 that's the answer

6 0

2 years ago

Explain three ways in which the sugar revolution impacted on the caribbean

denis-greek [22]

Answer:

During the colonial period, the arrival of sugar culture deeply impacted the society and economy in the Caribbean. It not only dramatically increased the ratio of slaves to free men, but it increased the average size of slave plantations

The negative impact of the slave trade on the development of the Caribbean islands. The slave trade had long lasting negative effects on the islands of the Caribbean. The native peoples, the Arawaks, were wiped out by European diseases and became replaced with West Africans

The sugar revolutions were both cause and consequence of the demographic revolution. Sugar production required a greater labor supply than was available through the importation of European servants and irregularly supplied African slaves

Explanation:

Hope this helps:)

6 0

2 years ago