Tutor profile: Francisca W.
¿Que tiempo hace en Chile en el mes de Mayo?
En Mayo, el tiempo en Chile es agradable por que es otoño.
Subject: Basic Math
Solve the following expression: 2x4+25+6-(2x5)
To solve this problem, we need to consider PEMDAS/GEMDAS, which outlines the order of operations for us. First, we will start with G - Groups. Do we see any groups in this problem? There is one - (2x5). Within each group, we reapply GEMDAS, however, since there is only one operation - multiplication - we can do this in one step. Our expression then looks like this: 2x4+25+6-(10). Next, we can look at E - exponents. There are no exponents, so we move on to MD - Multiplication and division from left to right. There is one multiplication, 2x4, which is 8. Let's rewrite our expression as 8+25+6-10. Now, we only have AS left, and we will perform addition and subtraction from left to right. 8+25 is 33, 33 + 6 is 39, and 39 - 10 is 29. Our final answer is 29.
How many moles are present in 64.0 grams of O2?
To answer this question, we need to understand the relationship between molecular weight/molar mass and moles. On the periodic table, Oxygen has an atomic mass of 16.0 g, so the mass of O2 is equal to two Oxygen atoms, so 16.0+16.0 = 32.0 g. The molar mass of O2 is then 32.0g. To find the number of moles, we can divide the given mass by the molar mass, in this case 64.0 g divided by 32.0 g. This is equal to 2, and considering significant figures, we should round our answer to 3 significant figures. The answer is then 2.00 moles of O2 are present in 64.0 grams.
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