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andrew-mc [135]
2 years ago
15

What three countries are considered the ‘big three’ when it comes to space programs and are the only countries to successfully l

aunch human missions to space?
A. Canada, the United States, and Japan
B. China, France, and the United States
C. United States, Russia, and China
D. Japan, United States, and France
Chemistry
1 answer:
Colt1911 [192]2 years ago
8 0

Answer:

C. United States, Russia, and China

Explanation:

Only three nations (Russia, U.S., China) have launched their own crewed spacecraft, with the Soviets/Russians and the American programs providing rides to other nations' astronauts. Twenty-seven "first flights" occurred on Soviet or Russian flights while the United States carried fourteen.

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What is the term for the smallest bit into which a chemical substance can be divided and still have the properties of that subst
ziro4ka [17]

Answer:

Molecule

Explanation:

molecule of the substance.  You can break the molecule down further, into the atoms that make it up, but those don't have the properties of the original  'compound'.

Here's an example:

-- Sodium is a soft, slippery metal, that explodes when water touches it.

-- Chlorine is a poisonous green gas.

When an atom of Sodium and an atom of Chlorine combine, they make one molecule of a substance called "Sodium Chloride".  That's SALT !  It isn't green, it isn't a gas, it isn't poisonous, it isn't soft and slippery, and it doesn't explode when water touches it.

3 0
3 years ago
The main types of chemical bonds are ________ and _______ bonds
Musya8 [376]

Answer:

covalent and ionic

Explanation:

covalent is nonmetal+nonmetal

ionic is metal+nonmetal

5 0
3 years ago
Making methanol the element hydrogen is not abundant in nature, but it is a useful reagent in, for example, the potential synthe
stealth61 [152]
ΔG⁰ = ΔH⁰ - TΔS
ΔH⁰ = Hf,(CH₃OH) - Hf,(CO) = -238.7 + 110.5 = -128.2 kJ/mol
ΔS = S(CH₃OH) - S(CO) - 2S(H₂) = 126.8 - 197.7 - 2 x 130.6 = -332.1 J/mol.K
So 
ΔG⁰ = - 128200 + 332.1 T
For the reaction to be spontaneous:
ΔG⁰ < 0
So: -128200 + 332.1 T < 0
332.1 T < 128200
T < 386.028 K
5 0
2 years ago
Lead(II) oxide from an ore can be reduced to elemental lead by heating in a furnace with carbon. Calculate the expected yield of
Lelu [443]

Answer:

53kg is the expected yield of lead

Explanation:

Firstly, in order to solve this question, we need to write the equation of reaction correctly. This is as follows:

PbO(s) + C(s) ---> Pb(l) + CO(g)

We proceed from here. We should get the limiting reactant but this can only be obtained by getting the number of moles of each reactant present.

The formula to use across all boards is that the number of moles is the mass of each of the reactant divided by the molar mass of each of the reactant.

For PBO, mass is 57kg = 57000g

Molar mass of PBO = 223.20g/mol

The number of moles is thus 57,000/223.2 = 255.37 moles

For carbon, mass is also 57kg = 57000g

Molar mass is 12g/mol

Number of moles of carbon = 57000/12 = 4750 moles

From the number of moles, we can see that the number of moles of Carbon is greater than that of PbO. This means that PbO is the limiting reagent.

Hence we use it to calculate percentage yield.

The number of moles of lead formed is the same of number of moles of lead oxide = 255.37 since we have mole ratio of 1 to 1

The molar mass of lead is 207.20g/mol

The mass of lead formed is = moles of lead formed * molar mass of lead = 207.20 * 255.37 = 52,912g which is approximately 53kg

Hence the expected yield is 53kg

6 0
3 years ago
Please help its urgent
mrs_skeptik [129]

Answer:

C

Explanation:

I picked C because the plant is interacting with the sun which is a nonliving part of the environment.

A, B and D are wrong because seaweed, horses, and trees are living things.

8 0
2 years ago
Read 2 more answers
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