Government should use informed science to help make policies protect all citizens True or False

What do the conclusions tell about the experiment?

Blababa [14]

Answer:

Option C

Explanation:

When you perform a experiment to test your hypothesis (your educated guess on what you think will happen) you complete trials to find data that is reliable and valid so you are only getting the best possible results. After you complete the experiment you write your conclusion which is when you take the data and you say if the data supported your hypothesis, if you did guess correctly at the beginning of the experiment. Which means the answer is option C "the conclusions tell why the data support or reject the hypothesis."

Hope this helps.

3 0

2 years ago

The law of conservation of mass states that in a chemical reaction, mass is neither created nor destroyed. that means, the total

g100num [7]

Well all reactions need energy to start it. The light is the energy that the reaction requires to start it. Sunlight also has no mass in the first place so laws of conservation of mass don't apply to it.

5 0

4 years ago

Read 2 more answers

What element has the same valence electrons as carbon A) N B) AI C) Si or D) Be

Rufina [12.5K]

Answer:

Si

Explanation:

The outer shells of both elements have 4 electrons

3 0

4 years ago

Percentage Yield

scoundrel [369]

Q.No. 1:

You have 20.0 g of CaCO₃. You decompose it by heat, and weigh the calcium oxide that remains. You have 10.3 grams. What is the % yield?

Answer:

%age Yield = 92.37 %

Solution:

The balance chemical equation for given decomposition reaction is;

CaCO₃ → CaO + CO₂

Step 1: Calculate Moles of CaCO₃:

Moles = Mass / M.Mass

Moles = 20.0 g / 100.08 g/mol

Moles = 0.199 moles of CaCO₃

Step 2: Calculate theoretical amount of CaO produced;

According to equation,

1 moles of CaCO₃ produced = 1 mole of CaO

So,

0.199 moles of CaCO₃ will produce = X moles of CaO

Solving for X,

X = 0.199 mol × 1 mol / 1 mol

X = 0.199 mol of CaO

Also,

Mass = Moles × M.Mass

Mass = 0.199 mol × 56.07 g/mol

Mass = 11.15 g of CaO

Step 3: Calculate %age Yield as;

%age Yield = Actual Yield / Theoretical Yield × 100

%age Yield = 10.3 g / 11.15 g × 100

%age Yield = 92.37 %

___________________________________________

Q.No. 2:

A student makes sodium chloride by buming 2.3 grams of sodium in chlorine gas. If the yield is 90%, how much sodium chloride is made?

Answer:

Actual Yield = 5.785 g of NaCl

Solution:

The balance chemical equation for given decomposition reaction is;

2 Na + Cl₂ → 2 NaCl

Step 1: Calculate Moles of Na:

Moles = Mass / M.Mass

Moles = 2.3 g / 23 g/mol

Moles = 0.10 moles of Na

Step 2: Calculate theoretical amount of NaCl produced;

According to equation,

2 moles of Na produced = 2 moles of NaCl

So,

0.10 moles of Na will produce = X moles of NaCl

Solving for X,

X = 0.10 mol × 2 mol / 2 mol

X = 0.10 mol of NaCl

Also,

Mass = Moles × M.Mass

Mass = 0.10 mol × 58.44 g/mol

Mass = 5.844 g of NaCl

Step 3: Calculate Actual Yield as;

%age Yield = Actual Yield / Theoretical Yield × 100

Or,

Actual Yield = %age Yield × Theoretical Yield ÷ 100

Actual Yield = 99 × 5.844 g ÷ 100

Actual Yield = 5.785 g of NaCl

___________________________________________

Q.No. 3:

For the chemical reaction Mg(s) + 2 HCl (aq) → H₂ (g) + MgCl₂ (aq) calculate the % yield if 100 grams of magnesium react with excess HCl to produce 310 grams of MgCl₂.

Answer:

%age Yield = 79.13 %

Solution:

The balance chemical equation for given decomposition reaction is;

Mg + 2 HCl → MgCl₂ + H₂

Step 1: Calculate Moles of Mg:

Moles = Mass / M.Mass

Moles = 100 g / 24.30 g/mol

Moles = 4.11 moles of Mg

Step 2: Calculate theoretical amount of MgCl₂ produced;

According to equation,

1 mole of Mg produced = 1 mole of MgCl₂

So,

4.11 moles of Mg will produce = X moles of MgCl₂

Solving for X,

X = 4.11 mol × 1 mol / 1 mol

X = 4.11 mol of MgCl₂

Also,

Mass = Moles × M.Mass

Mass = 4.11 mol × 95.21 g/mol

Mass = 391.73 g of MgCl₂

Step 3: Calculate %age Yield as;

%age Yield = Actual Yield / Theoretical Yield × 100

%age Yield = 310.0 g / 391.73 g × 100

%age Yield = 79.13 %

5 0

4 years ago

Most of the deserts on the Earth are located around 30°N & 30°S latitude. This is because air is ( rising / sinking ) at the

pashok25 [27]

Answer: We live at the bottom of a gaseous envelope the atmosphere--that is bound gravity to the planet Earth. The circulation of our atmosphere is a complex process because of the Earth's rotation and the tilt of its axis. The Earth's axis is inclined 23.5° from the ecliptic, the plane of the Earth's orbit around the Sun. Due to this inclination, vertical rays of the Sun strike 23.5° N. latitude, the Tropic of Cancer, at summer solstice in late June. At winter solstice, the vertical rays strike 23.5° S. Latitude, the Tropic of Capricorn. In the Northern Hemisphere, the summer solstice day has the most daylight hours, and the winter solstice has the fewest daylight hours each year. The tilt of the axis allows differential heating of the Earth's surface, which causes seasonal changes in the global circulation. On a planetary scale, the circulation of air between the hot Equator and the cold North and South Poles creates pressure belts that influence weather. Air warmed by the Sun rises at the Equator, cools as it moves toward the poles, descends as cold air over the poles, and warms again as it moves over the surface of the Earth toward the Equator. This simple pattern of atmospheric convection.

3 0

3 years ago